Private developer tools that run in your browser

Format JSON, convert PDFs, decode JWTs, optimize images, generate hashes, test regex and more — privacy-first tools built for everyday developer workflows.

ArrayKit is a privacy-first developer toolbox for JSON formatting, PDF tools, API utilities, encoding/decoding, security checks, regex testing, and browser-based file processing.

Popular tools

  • JSON Formatter — Beautify, minify and validate JSON with error locations.
  • JSON Viewer — Text + collapsible tree viewer with expand/collapse and node paths.
  • JSON to TypeScript — Generate TypeScript interfaces from a JSON sample.
  • JWT Decoder — Decode JWT header & payload and inspect exp / iat (no verification).
  • Base64 Encode / Decode — UTF-8 safe Base64 encoding and decoding.
  • Text Diff — Compare two texts line-by-line and see additions and removals.
  • Merge PDFs — Combine multiple PDFs into one, with reordering.
  • Image Optimizer — Re-encode and shrink images (JPEG/WebP/PNG), optionally resizing.
  • Regex Tester — Test regular expressions live with matches, groups and flags.
  • SQL Formatter — Format SQL for MySQL, PostgreSQL, SQL Server, SQLite, BigQuery and Oracle.
  • cURL to Fetch — Convert a curl command to a JavaScript fetch() call.
  • Internet Speed Test — Measure your download speed, upload speed, ping and jitter, and see what your connection can handle.
  • Countdown Timer — Set hours, minutes and seconds and get an alarm when time is up — presets, full screen and a share link.
  • Typing Speed Test — Measure your typing speed in WPM with accuracy, consistency and a per-second chart.
  • Image Resizer — Resize photos by pixels, percentage, preset or longest side — in batches, with a ZIP download.
  • HEIC to JPG Converter — Convert iPhone HEIC photos to JPG, PNG or WebP in your browser, in batches, and download them as a ZIP.
  • Spin the Wheel — Add names or options, spin a colorful wheel and let chance pick the winner, with weights, sound and history.
  • Online Notepad — A private notepad that saves automatically in your browser, with multiple notes, search, word count and .txt export.

Guides

  • Image Size, Resolution and DPI, Explained — What image dimensions, DPI and file size mean, how to pick the right pixel size for web and print, and why resizing is not the same as compressing or cropping.
  • Internet Speed Test Results, Explained — What download speed, upload speed, ping, jitter and bufferbloat mean, how much speed streaming, calls and gaming need, and why you get less than your plan.
  • BPM, Tempo and the Metronome, Explained — What BPM means, how tempo markings like Allegro map to beats per minute, how time signatures and subdivisions work, and how to practice with a metronome.
  • The Pomodoro Technique, Explained — How the Pomodoro Technique works: the 25-minute focus session, the 5-minute break, the long break after four, popular variations like 50/10, and tips that help.
  • QR Codes: Error Correction, Size and Logos, Explained — How QR error correction works, how large a logo can be, what size to print, which colors scan reliably, and when to use PNG or SVG so your code always scans.
  • Typing Speed and WPM, Explained — How WPM is calculated, how net and raw speed differ, what counts as a good typing score, and how to type faster with fewer mistakes. Test your speed online.
  • Base64 Encoding, Explained — Base64 explained: how it turns binary into text, the alphabet and padding, the URL-safe variant, size overhead, use cases, and why it isn't encryption.
  • JSON Formatting, Explained — A complete guide to JSON: what it is, its data types and syntax rules, beautify vs minify, validation and JSON Schema, common errors, and best practices.
  • JSON Web Tokens (JWT), Explained — A complete guide to JWTs: the three-part structure, header and payload claims, signing algorithms, decoding vs verifying, and the security pitfalls to avoid.

All guides

Your data stays on your device

ArrayKit is built for fast, privacy-first developer workflows. Format, convert, debug, validate and generate directly in your browser — sensitive content never has to be uploaded to a server.

Browser-based processing

Every tool runs locally in your browser, so the data you work with stays on your device.

Developer-friendly workflows

Built for daily tasks: formatting JSON, debugging APIs, converting files, validating data and generating secure values.

Fast access

Open a tool and start working immediately. Account features are planned for saved tools, preferences, history and team workflows.

All tools by category

JSON

  • JSON Formatter — Beautify, minify and validate JSON with error locations.
  • JSON Tree Viewer — Explore JSON as a collapsible, typed tree.
  • JSON Viewer — Text + collapsible tree viewer with expand/collapse and node paths.
  • JSON to TypeScript — Generate TypeScript interfaces from a JSON sample.
  • JSON to CSV — Convert an array of flat JSON objects to CSV.
  • JSON Escape / Unescape — Escape text into a JSON string or unescape a JSON string back to raw text.
  • JSON to Code — Generate Go, Rust, Python, Java, Kotlin, C# and TypeScript types from JSON.
  • JSON Diff — Compare two JSON documents and see a structural, key-order-independent diff.
  • JSON Schema Generator & Validator — Generate a JSON Schema from a sample or validate JSON against a schema.
  • JSON Flatten / Unflatten — Flatten nested JSON to dot-notation keys, or unflatten it back.
  • JSON to Zod — Generate a Zod schema (TypeScript) from a JSON sample.
  • JSON to Pydantic — Generate Pydantic v2 model classes from a JSON sample.
  • JSONPath Evaluator — Query JSON with a JSONPath expression and see matched values and paths live.
  • JSON to TOON — Convert JSON to TOON (Token-Oriented Object Notation) and back, with an LLM token savings estimate.
  • jq Playground — Run jq filters against JSON in your browser — map, select, group_by and more, with the real jq engine.
  • TypeScript to Mock JSON — Generate realistic mock JSON from a TypeScript interface or type.
  • JSON Schema Sample Data Generator — Generate realistic sample JSON that conforms to a JSON Schema.
  • JSON to XML Converter — Convert JSON to XML and XML back to JSON, in your browser.
  • NDJSON to JSON — Convert NDJSON / JSON Lines to a JSON array and back, line by line.
  • Sort JSON Keys — Recursively sort JSON object keys alphabetically, with pretty-print and reverse options.
  • CSV to JSON — Convert CSV or TSV to JSON with type inference and nested keys, in your browser.
  • Excel to JSON — Convert an .xlsx or .xls spreadsheet to JSON, with sheet and header options, in your browser.
  • Excel to CSV — Convert an .xlsx or .xls spreadsheet to clean CSV or TSV, in your browser.
  • CSV to SQL — Convert CSV to SQL INSERT and CREATE TABLE statements for MySQL, PostgreSQL and SQLite.
  • HTML Table to JSON — Extract HTML tables into JSON or CSV, honoring headers and colspan, in your browser.
  • JSON Patch Generator — Generate an RFC 6902 JSON Patch between two JSON documents and apply a patch to a source.
  • JSON Repair — Fix broken or LLM-generated JSON: trailing commas, single quotes, unquoted keys and comments.
  • JSON to GraphQL Schema — Generate GraphQL SDL types from a JSON sample, inferring fields and nested types.
  • JSON to SQL — Turn a JSON array into CREATE TABLE and batched INSERTs with inferred column types.

Code Formatters

  • YAML ↔ JSON — Convert YAML to JSON and back.
  • Markdown Preview — Render Markdown to HTML with a live preview.
  • Regex Tester — Test regular expressions live with matches, groups and flags.
  • CSS Color Converter — Convert between HEX, RGB and HSL with a live swatch.
  • Text Diff — Compare two texts line-by-line and see additions and removals.
  • MDX Converter — Render MDX as formatted text, convert HTML → MDX, and escape text to literal MDX.
  • CSS / SCSS Formatter — Beautify or minify CSS/SCSS/LESS, sort properties and remove duplicates.
  • JS / TS Formatter — Beautify or minify JavaScript, TypeScript and JSX/TSX with Prettier options.
  • HTML Formatter — Beautify or minify HTML, format inline CSS/JS, and preview the result.
  • XML Formatter — Beautify, minify and validate XML, and convert XML ↔ JSON.
  • SQL Formatter — Format SQL for MySQL, PostgreSQL, SQL Server, SQLite, BigQuery and Oracle.
  • GraphQL Formatter — Format or minify GraphQL queries and schemas, validate syntax and extract operations.
  • Dockerfile Formatter — Format a Dockerfile and get best-practice / lint suggestions.
  • MongoDB Query Formatter — Format MongoDB shell queries and aggregation pipelines.
  • Contrast Checker — Check WCAG colour contrast ratio and AA/AAA pass for any two colours.
  • Mermaid Diagram Renderer — Render Mermaid diagrams (flowcharts, sequence, gantt) to SVG in your browser.
  • SVG Optimizer — Minify SVG — strip comments, metadata and editor cruft, and collapse whitespace.
  • MongoDB Query Beautifier — Beautify and indent MongoDB queries and find() statements in your browser.
  • MongoDB Aggregation Beautifier — Beautify and indent MongoDB aggregation pipelines in your browser.
  • MongoDB Explorer — Explore a MongoDB document or collection sample and infer its field schema and types.
  • OpenAPI / Swagger Formatter — Format and validate OpenAPI / Swagger specs (JSON or YAML) and count paths and operations.
  • CSS Unit Converter — Convert between px, rem, em, pt and % live with a configurable root font size.
  • Glob to Regex — Convert a glob or wildcard pattern into an equivalent JavaScript regex.
  • HTML to Markdown — Paste HTML and convert it to clean Markdown live, with GFM tables, lists and code blocks.
  • TOML Formatter & Converter — Format and validate TOML, and convert TOML ↔ JSON.
  • logfmt to JSON — Convert logfmt key=value logs to JSON and back.
  • dotenv to JSON — Convert a .env file to JSON and JSON back to .env, with quoting and comments handled.
  • CSV to Markdown Table — Convert CSV or TSV data into a Markdown table, with alignment and header options.
  • INI to JSON — Convert INI config files to JSON and JSON back to INI, with sections and comments.
  • Markdown Table Generator — Build a table in an editable grid and export Markdown, HTML, AsciiDoc and LaTeX.
  • Data Size Converter — Convert between bits, bytes, KB, MB, GB and KiB, MiB, GiB, with decimal and binary units.
  • Java Properties ↔ JSON — Convert Java .properties files to JSON and JSON back to .properties, in your browser.

Text

  • Case Converter — Convert text between camelCase, snake_case, kebab-case, PascalCase and more.
  • Lorem Ipsum Generator — Generate placeholder lorem ipsum paragraphs, sentences or words.
  • Mock Data Generator — Generate fake JSON data — names, emails, UUIDs, dates and more.
  • Word & Character Counter — Count words, characters, sentences, lines, bytes and approximate tokens, live.
  • Slug Generator — Turn a title into a clean, URL-safe slug, with batch mode.
  • LinkedIn Text Formatter — Add bold, italic, underline and more to LinkedIn posts using Unicode you can paste anywhere.
  • AI Text Cleaner — Detect and remove invisible characters and typography artifacts left by AI models and copy-paste.
  • Remove Duplicate Lines — Remove duplicate lines from a list, with case, trim, keep-first-or-last and sort options.
  • Fake VAT Number Generator — Generate format-valid, check-digit-correct fake VAT numbers for testing invoices and checkout forms.
  • Sort Text Lines — Sort lines alphabetically, numerically, by length or randomly, with reverse, case and dedupe options.
  • Find and Replace Text — Find and replace text with plain or regex search, case sensitivity, whole-word and global options.
  • NATO Phonetic Alphabet — Convert text to the NATO phonetic alphabet (Alfa, Bravo, Charlie) and spell it back.
  • Delimiter Converter — Convert a list of lines to a comma, tab or custom delimited list and back, with quoting.
  • Fancy Text Generator — Turn plain text into bold, italic, script and other Unicode font styles you can copy.
  • Remove Line Breaks — Remove or replace line breaks and join paragraphs, with options to keep blank lines.
  • Title Case Converter — Capitalize titles correctly with AP, Chicago, APA and MLA style rules, in your browser.
  • Readability Score Checker — Score text with Flesch-Kincaid, Gunning Fog, SMOG and more, with word and syllable stats.
  • Number to Words Converter — Convert numbers and currency amounts into written words, with cardinal and ordinal forms.
  • AI Text Summarizer — Summarize long text into a short summary — the AI model runs in your browser, nothing is uploaded.
  • AI Sentiment Analyzer — Detect the tone of text as positive or negative with a confidence score — runs in your browser.
  • AI Entity & PII Extractor — Extract names, organizations, locations, emails, phone numbers and IPs from text — runs in your browser.
  • Local AI Chat — Chat with an AI assistant that runs entirely in your browser on your own device. Your conversation is never uploaded.
  • Reverse Text — Reverse text by character, word or line, with Unicode-safe grapheme handling.
  • Character Frequency Counter — Count how often each character or word appears in text, sorted by frequency.
  • Upside Down Text Generator — Flip text upside down using Unicode look-alikes you can paste anywhere.
  • Word Cloud Generator — Paste text and get a word cloud — stop words, shapes, colours and PNG or SVG download.
  • Online Notepad — A private notepad that saves automatically in your browser, with multiple notes, search, word count and .txt export.
  • Text to Speech — Read any text aloud with the voices on your device: choose language, speed and pitch, with word highlighting.
  • Emoji Picker — Search and copy emoji with one click: skin tones, categories, recent picks, shortcodes and Unicode codes.

Encode / Decode

  • Base64 Encode / Decode — UTF-8 safe Base64 encoding and decoding.
  • URL Encode / Decode — Encode and decode URL components.
  • HTML Escape / Unescape — Escape and unescape HTML special characters and entities.
  • Number Base Converter — Convert integers between binary, octal, decimal and hex.
  • QR Code Generator — Generate a QR code from text or a URL; download as PNG or SVG.
  • Mojibake / Encoding Fixer — Fix garbled "mojibake" text from an encoding mismatch — turn Café back into Café.
  • Protobuf Decoder — Decode a Protocol Buffers binary message (hex or base64) without a .proto schema.
  • Base32 Encoder / Decoder — Encode text to Base32 and decode Base32 back to text (RFC 4648), in your browser.
  • Morse Code Translator — Translate text to Morse code and Morse code back to text, with audio playback.
  • Text to Binary Converter — Convert text to binary, and binary, hex or decimal back to text, in your browser.
  • Base58 Encoder / Decoder — Encode and decode Base58 (Bitcoin / IPFS alphabet), with hex and text input.
  • ULID Generator — Generate sortable ULIDs and decode a ULID to its timestamp, in your browser.
  • Snowflake ID Generator — Generate and decode Twitter and Discord style Snowflake IDs, with timestamp extraction.
  • Caesar Cipher / ROT13 — Encode and decode Caesar, ROT13, ROT47 and Atbash ciphers, with a brute-force cracker.
  • Roman Numeral Converter — Convert numbers to Roman numerals and Roman numerals back to numbers, both ways.
  • Bitwise Calculator — Apply AND, OR, XOR, NOT and bit shifts to integers, with binary, hex and decimal views.
  • IEEE 754 Converter — Convert decimals to and from 32-bit and 64-bit IEEE 754 floating-point, with the bit fields.
  • Punycode Converter — Convert internationalized domain names between Unicode and ASCII Punycode (xn--), both ways.
  • Quoted-Printable Encoder / Decoder — Encode and decode Quoted-Printable (MIME =XX) text, in your browser.
  • Ascii85 / Base85 Encoder / Decoder — Encode and decode Ascii85 and Z85 Base85, in your browser.
  • Unicode Escape / Unescape — Escape text to Unicode escape sequences and unescape them back.
  • Hex Dump Viewer — View text or a file as a classic hex + ASCII dump, with adjustable width.
  • Nano ID Generator — Generate URL-safe, collision-resistant Nano IDs with a custom size and alphabet.
  • Vigenère Cipher — Encode and decode Vigenère, autokey and Beaufort ciphers, with key-length hints.
  • QR Code Reader — Scan a QR code from an image, a screenshot or your camera and see what is inside — links, Wi-Fi, contacts and payments.
  • QR Code with Logo — Put your logo in a QR code and restyle its colours, shapes and frame, with a live check that it still scans.
  • UPI QR Code Generator — Make a UPI payment QR code from a UPI ID with an optional amount and note, and print a Scan to pay card.
  • vCard QR Code Generator — Turn contact details into a QR code phones can save in a tap, as vCard 3.0, 4.0 or MECARD, with a .vcf download.
  • WhatsApp QR Code Generator — Create a wa.me chat link and QR code from a phone number and an optional first message.
  • Bulk QR Code Generator — Turn a list or a CSV into up to 500 QR codes as a ZIP of PNG or SVG files, or a printable labelled sheet.

Images

  • Image Optimizer — Re-encode and shrink images (JPEG/WebP/PNG), optionally resizing.
  • Image Format Converter — Convert images between PNG, JPEG and WebP entirely in your browser.
  • EXIF Viewer & Remover — View and strip EXIF metadata (including GPS) from photos — nothing is uploaded.
  • Base64 Image Encoder / Decoder — Convert images to Base64 Data URIs with ready-made HTML and CSS snippets, or decode a Data URI back to a downloadable image.
  • App Icon Generator — Turn one image into every iOS, macOS and Android app icon size — downloaded as a ZIP, in your browser.
  • Sprite Sheet CSS Animation Generator — Turn a sprite sheet into a copy-paste CSS @keyframes animation using steps(), with a live preview.
  • SVG to PNG Converter — Convert SVG to PNG or JPG at any scale, with a transparent or solid background, in your browser.
  • Image Color Picker — Upload an image and pick colors from any pixel to get HEX, RGB and HSL values, in your browser.
  • Color Format Converter — Convert a color across HEX, RGB, HSL, HWB, LAB, LCH and OKLCH with a live swatch.
  • Barcode Generator — Generate EAN, UPC, Code 128 and Code 39 barcodes and download them as SVG or PNG.
  • Image Color Palette Extractor — Extract a dominant color palette from an image as HEX, RGB and HSL with CSS variables.
  • Flip & Rotate Image — Rotate by 90° and flip images horizontally or vertically, then download — in your browser.
  • Image Cropper — Crop an image to any area or fixed aspect ratio and download it, in your browser.
  • Image Watermark — Add a text or logo watermark to an image, anchored or tiled, with opacity and rotation.
  • Blur & Redact Image — Permanently blur, pixelate or black out parts of a screenshot before sharing it.
  • Round Image Corners — Clip photos to rounded rectangles or circles and export PNGs with transparent corners.
  • Color Blindness Simulator — See any image the way people with protanopia, deuteranopia or tritanopia see it.
  • Image DPI Changer — Set a PNG or JPEG’s DPI for print without recompressing a single pixel.
  • BlurHash Generator — Turn an image into a BlurHash string, and decode any hash back to a preview.
  • Placeholder Image Generator — Make placeholder images at any size, as SVG, PNG or a data URI.
  • ASCII Art Generator — Convert any image into ASCII art, with character sets, contrast and invert.
  • Image Filters — Apply grayscale, sepia, contrast, blur and more, then export the PNG and the CSS.
  • Image Splitter — Cut a picture into a grid of tiles and download them as a ZIP.
  • Image Merger — Combine images side by side, stacked or in a grid, with gaps and a background.
  • Collaborative Whiteboard — Draw together with someone over a direct browser-to-browser connection.
  • Thumbmark Maker — Turn a photo of an inked thumbprint into a clean transparent PNG for forms.
  • Signature Background Remover — Lift a signature off a photo of paper into a transparent PNG, in the ink colour you pick.
  • Image to Text (OCR) — Pull the text out of photos, screenshots and scans with on-device recognition.
  • Image Resizer — Resize photos by pixels, percentage, preset or longest side — in batches, with a ZIP download.
  • Compress Image to Size — Bring a photo under an exact size such as 20 KB, 50 KB, 100 KB or 200 KB.
  • Passport Photo Maker — Crop a photo to passport and ID sizes and lay out a print-ready sheet of copies.
  • Favicon Generator — Make favicon.ico, PNG sizes, an Apple touch icon and a web manifest from an image, letters or an emoji.
  • GIF Maker — Turn a set of images into an animated GIF with frame delays, looping and a colour palette.
  • Meme Generator — Put top and bottom captions or free-placed text on any image and save it as PNG or JPEG.
  • Chart Maker — Turn pasted data into bar, line, area, pie and doughnut charts you can download as PNG or SVG.
  • HEIC to JPG Converter — Convert iPhone HEIC photos to JPG, PNG or WebP in your browser, in batches, and download them as a ZIP.
  • PNG to SVG Converter — Turn PNG, JPG and other bitmaps into scalable SVG vectors with adjustable colors and detail.

Video

  • Video Compressor — Compress video files in your browser — adjustable quality, resolution and format, nothing uploaded.
  • Video Converter — Convert MOV, MKV, AVI, WebM and MP4 videos to MP4 or WebM in your browser — nothing uploaded.
  • Video Trimmer — Cut a clip from a video by start and end time, in your browser — nothing uploaded.
  • Extract Audio from Video — Extract the audio from a video as MP3, WAV or M4A, in your browser — nothing uploaded.
  • Mute Video — Remove the audio track from a video in your browser — nothing uploaded.
  • Add Music / Replace Audio — Replace the audio in a video with your own music and adjust the volume, in your browser.
  • Video Resizer — Resize video for Reels, YouTube, square and more with letterboxing, in your browser.
  • Crop Video — Crop a video to square, vertical or landscape and trim the edges, in your browser.
  • Video to GIF — Turn a clip of a video into an optimized animated GIF, in your browser — nothing uploaded.
  • GIF to Video — Convert an animated GIF to MP4 or WebM for smaller size and easy sharing, in your browser.
  • Video Thumbnail Generator — Auto-generate still frames from a video and download them as JPG, PNG or WebP.
  • Screenshot from Video — Capture the current frame of a video as a PNG, JPEG or WebP image, in your browser.
  • Split Video — Split a video into multiple parts by time or count and download them as a ZIP, in your browser.
  • Add Watermark to Video — Overlay a text or logo watermark on a video with position and opacity control, in your browser.
  • Video Speed Changer — Speed up or slow down a video, re-timing the audio to match, in your browser.
  • Video Merger — Join clips into one video — lossless when they match, auto-scaled to MP4 when not.
  • Audio Converter — Convert audio between MP3, WAV, FLAC, M4A and OGG with bitrate control.
  • Subtitle Converter — Convert SRT, WebVTT, SBV and ASS subtitles, and fix timing that drifts.
  • Video Bitrate Calculator — Turn a target file size into a bitrate, or a bitrate into a file size.
  • Rotate Video — Turn or mirror a video, by re-encoding the frames or just the rotation flag.
  • Audio Trimmer — Cut a clip from an audio file with optional fades, losslessly where possible.
  • Audio Volume Changer — Raise, lower or normalise the volume of a video or audio file in your browser.
  • Video Frame Rate Converter — Change a video to 24, 30, 60 fps or any rate, with interpolation or retiming.
  • Screen Recorder — Record your screen, a window or a tab with optional microphone, then save a WebM or MP4.
  • Voice Recorder — Record from your microphone, trim the take and save it as WAV or the original format.
  • Audio to Text — Transcribe a recording or a video's audio into text, SRT or VTT — on your device.

PDF

  • Image to PDF — Combine images into a single PDF (auto / portrait / landscape).
  • PDF to Images — Render PDF pages to PNG or JPG images you can download.
  • Merge PDFs — Combine multiple PDFs into one, with reordering.
  • Split PDF — Extract pages or ranges (e.g. 1-3,5,7-9) into a new PDF.
  • Rotate PDF — Rotate all pages or a selection by 90/180/270°.
  • Organize PDF — Reorder, rotate and delete pages from thumbnails, then export.
  • Add Page Numbers — Stamp page numbers onto a PDF (position, format, start).
  • Watermark PDF — Add a diagonal text watermark to every page.
  • Crop PDF — Trim margins from every page via the crop box.
  • PDF to Text — Extract selectable text from a PDF as plain text or Markdown.
  • Compare PDFs — Diff the extracted text of two PDFs line-by-line.
  • Encrypt PDF — Password-protect a PDF with AES-256 or RC4 encryption.
  • Decrypt PDF — Remove password protection from an encrypted PDF.
  • Compress PDF — Shrink a PDF by re-rendering each page to a JPEG at a chosen quality and resolution.
  • PDF Metadata Editor — View, edit or strip a PDF’s title, author, subject, keywords and producer.
  • Resize PDF — Rescale every PDF page to A4, Letter or another standard size, content centred.
  • Flatten PDF — Lock filled form fields into the page so a PDF looks the same everywhere.
  • PDF N-up — Print 2, 4, 9 or 16 pages per sheet, with a booklet option for folding.
  • Interleave PDF Pages — Merge odd and even scan passes back into one document, reversing if needed.
  • PDF to Single Long Page — Stack every page onto one continuous sheet you scroll instead of paging.
  • PDF Form Data Extractor — Pull the answers out of a filled PDF form as JSON or CSV, field by field.
  • Blank Page Remover — Find and delete blank pages from a scan, with a tolerance you control.
  • Text to PDF — Turn typed or pasted text into a paginated, downloadable PDF.
  • Markdown to PDF — Render Markdown — headings, lists, tables and code — as a PDF.
  • HTML to PDF — Convert HTML markup into a clean, paginated PDF document.
  • CSV to PDF — Lay CSV rows out as a bordered, paginated PDF table.
  • Excel to PDF — Turn spreadsheet sheets into printable PDF tables.
  • Word to PDF — Convert a .docx document into a PDF, keeping its structure.
  • PowerPoint to PDF — Turn a .pptx deck into a PDF, one page per slide.
  • EPUB to PDF — Convert an EPUB book into a paginated PDF you can print.
  • PDF to Word — Rebuild a PDF as an editable .docx document.
  • PDF to Excel — Pull the tables out of a PDF into an .xlsx workbook or CSV.
  • PDF to PowerPoint — Turn PDF pages into .pptx slides — as pictures or editable text.
  • PDF to HTML — Convert a PDF into clean, searchable, responsive HTML.
  • PDF to EPUB — Turn a PDF into a reflowable EPUB for e-readers and phones.
  • PDF to ZIP — Export every page as its own file inside one archive.
  • PDF Header and Footer — Stamp a running header and footer onto every page.
  • Redact PDF — Black out words and areas so they are gone from the file.
  • Invert PDF Colours — Make a dark-mode, sepia or greyscale copy of a PDF.
  • Repair PDF — Diagnose a broken PDF and rebuild what can be recovered.
  • Edit PDF Text — Cover a mistake on a page and type the correction over it.
  • PDF Read Aloud — Listen to a PDF read out loud, passage by passage.
  • PDF Summarizer — Summarise a long PDF section by section, on your device.
  • Scan to PDF — Use a camera as a document scanner and save the pages as a PDF.
  • PDF OCR — Recognise the text in a scanned PDF and make it searchable.
  • Sign PDF — Draw a signature and place it on a PDF page, with an optional printed name and date.
  • Fill PDF Form — Type into a fillable PDF form, then save it filled or flattened.
  • Extract Images from PDF — Pull the embedded photos and logos out of a PDF at their stored resolution.
  • Bates Numbering — Stamp a continuous prefixed number across a set of PDFs and export the index.
  • Flip PDF Pages — Mirror PDF pages left to right or top to bottom, for transfers or a mirrored scan.
  • Split PDF by Size — Cut a PDF into parts that each stay under a file-size limit.
  • Split PDF Pages in Half — Turn scanned two-page spreads into single pages by cutting each sheet in half.
  • Split PDF by Bookmarks — Cut a report or book into separate files at its own outline entries.
  • Split PDF by Text — Start a new file wherever a page contains a phrase — one invoice per file.
  • Compress PDF to Size — Bring a PDF under an exact byte target such as 100 KB, 200 KB or 2 MB.
  • PDF to Handwriting — Rewrite the words in a PDF as handwritten pages on ruled or plain paper.
  • Text to Handwriting — Turn typed text into a handwritten page you can save as a PDF or an image.
  • Resume Builder — Fill in your details and get a clean single-column CV that parsers can read.
  • LaTeX Resume Generator — Fill in your details and export compilable .tex source in one of four typeset templates.
  • Handwriting to Text — Read handwritten pages into typed text, keeping each word where it was written.
  • PDF Workflow Builder — Chain rotate, crop, number, watermark, compress and more into one pass.
  • Audio to PDF Transcript — Transcribe a recording on your device and export it as a PDF, SRT or VTT.
  • PDF Recipient Copies — Make one visibly named copy per recipient, with a log of who received which.
  • Chat with PDF — Ask questions about a document with a model that runs on your own device.
  • Make PDF Look Scanned — Give a digital PDF the tilt, grain and grey tone of a page that went through a scanner.
  • TIFF to PDF — Convert single or multi-page TIFF files, including fax scans, into one PDF.
  • PDF to TIFF — Render PDF pages into a multi-page TIFF in colour, greyscale or black and white.
  • Deskew PDF — Straighten crooked scanned pages automatically, with a per-page angle you can adjust.
  • PDF Bookmark Editor — Add, rename, nest and reorder the bookmarks in a PDF, or generate them from headings.
  • PDF Attachments — List, extract, add or remove the files embedded inside a PDF.
  • Remove PDF Annotations — Strip comments, highlights, drawings and stamps from a PDF, keeping links if you like.
  • Remove Images from PDF — Blank out the pictures in a PDF for a lighter, text-only copy, keeping logos if you choose.
  • PDF Inspector — See a PDF’s version, page sizes, fonts, images, forms, security and standards claims.
  • PDF Font Finder — List every font a PDF uses, which pages use it and whether it is embedded.
  • Extract Links from PDF — Collect every clickable link and written URL in a PDF, with page numbers, as CSV.
  • PDF Word Counter — Count words, characters and pages in one or more PDFs, with a per-page breakdown.
  • PDF Page Counter — Count pages across many PDFs, split colour from black-and-white, and estimate print cost.
  • Make PDF Fillable — Draw text boxes, checkboxes and dropdowns onto a PDF to turn it into a fillable form.
  • Add Image to PDF — Place a logo, photo or stamp on chosen PDF pages with size, position and opacity control.
  • Overlay PDF (Letterhead) — Lay a letterhead or background PDF under or over every page of another PDF.
  • Add Margins to PDF — Add white space around PDF pages for binding, notes or bleed, per side or all round.
  • SVG to PDF — Convert SVG graphics to PDF, keeping shapes as vectors where possible.
  • EML to PDF — Turn saved email files into PDFs with the headers, message body and attachment list.
  • CBZ to PDF — Turn a CBZ comic archive into a PDF with pages in reading order.
  • PDF to CBZ — Package PDF pages as a CBZ comic archive for comic and manga readers.

Date / Time

  • Unix Timestamp Converter — Convert between Unix timestamps and human dates (local + UTC).
  • UUID Generator — Generate one or many random UUID v4 values.
  • Cron Explainer — Explain a cron expression and preview its next run times.
  • World Clock & Time Zone Converter — Compare times across cities on an aligned 24-hour grid and plan meetings — right in your browser.
  • Cron Expression Generator — Visually build a cron expression with live preview, a plain-English summary and next run times.
  • Date Duration Calculator — Calculate the duration between two dates in years, months, weeks, days and business days.
  • Age Calculator — Calculate exact age in years, months and days as of any date, plus totals in weeks, days, hours and next birthday.
  • Duration Converter — Convert a duration between seconds, minutes, hours, days, HH:MM:SS and human formats.
  • Business Days Calculator — Add or subtract working days from a date, or count business days between two dates.
  • Date Calculator — Add or subtract years, months, weeks and days from a date to find the resulting date.
  • Time Duration Calculator — Calculate the hours and minutes between two times of day, even across midnight.
  • ISO Week Number Calculator — Find the ISO-8601 week number for any date, and the date range for a given week.
  • strftime Date Formatter — Format a date with strftime tokens (%Y, %m, %d…) and preview the output live.
  • Relative Time Formatter — Turn a date into a human "time ago" phrase, or humanize a duration.
  • Time Calculator — Add or subtract times and durations, and sum multiple time spans.
  • Time Card Calculator — Total daily and weekly work hours from clock-in/out times minus breaks.
  • Day of the Week Calculator — Find the day of the week for any date, past or future.
  • Sunrise & Sunset Calculator — Sunrise, sunset, solar noon, twilight and golden hour for any date and location.
  • Moon Phase Calculator — Moon phase, illumination and age for any date, with a full-month phase calendar.
  • ISO 8601 Duration Converter — Read and write ISO 8601 durations like PT1H30M, in seconds and plain English.
  • ICS Calendar File Generator — Build an .ics invite with reminders, repeats, attendees and a time zone.
  • Julian Date Converter — Convert calendar dates to Julian Day, MJD and the YYDDD ordinal form.
  • Fiscal Quarter Calculator — Find the fiscal quarter and year for any date, on any financial calendar.
  • Stopwatch — A stopwatch with laps, splits and CSV export that keeps true time in a background tab.
  • Countdown Timer — Set hours, minutes and seconds and get an alarm when time is up — presets, full screen and a share link.
  • Pomodoro Timer — Focus and break cycles with long breaks, session counts and a local daily tally.
  • Alarm Clock — Set one or more alarms with labels, repeat days and snooze — rings while this tab stays open.
  • Interval Timer — Work, rest, rounds and sets with beeps — Tabata, HIIT, EMOM and boxing presets.
  • Countdown to a Date — Live days, hours, minutes and seconds until any date, with holiday shortcuts and a shareable link.

Web & DevOps

  • Chmod Calculator — Convert Unix file permissions between octal and symbolic (rwx).
  • .gitignore Generator — Build a .gitignore from common language and tool templates.
  • HTTP Status & MIME Types — Searchable reference of HTTP status codes and MIME content types.
  • Open Graph Generator — Generate Open Graph & Twitter meta tags with a live social-card preview.
  • robots.txt Generator — Visually build a robots.txt with user-agent rules, allow/disallow paths, crawl-delay and sitemaps.
  • XML Sitemap Generator — Turn a list of URLs into a standards-compliant sitemap.xml with optional lastmod, changefreq and priority.
  • .htaccess Generator — Toggle and configure common Apache .htaccess snippets with live output.
  • Nginx Config Generator — Build an nginx server block (static, reverse proxy, SSL, gzip, caching) from simple toggles.
  • Semver Calculator — Parse, compare, range-check, increment, and coerce semantic versions.
  • Cache-Control Header Builder — Assemble a correct HTTP Cache-Control header from plain toggles and human time units, with copy-ready nginx, Apache, and meta snippets.
  • Meta Tag Generator — Generate SEO, Open Graph and Twitter Card meta tags for your page from a simple form.
  • CSP Header Generator — Build a Content-Security-Policy header from directive toggles, with report-only and copy output.
  • htpasswd Generator — Generate Apache/nginx .htpasswd entries with bcrypt or SHA-1 hashed passwords, in your browser.
  • Tailwind Color Generator — Generate a full 50-950 Tailwind color scale from one brand color, with config-ready output.
  • CSS Grid Generator — Build CSS grid layouts visually and copy grid-template-columns, rows and gap.
  • CSS Clamp Calculator — Calculate a fluid CSS clamp() value from min and max sizes and viewport widths.
  • Cubic Bezier Generator — Design a cubic-bezier() easing curve with draggable handles and an animated preview.
  • Redirect Map Generator — Turn an old-to-new URL list into 301 redirect rules for nginx, Apache, Netlify and Vercel.
  • JSON-LD Generator — Generate schema.org JSON-LD structured data for Article, Product, FAQ and more from a form.
  • Query String to JSON — Convert a URL query string to JSON and back, handling nested keys and repeated params.
  • HTML to JSX Converter — Convert HTML to valid React JSX: className, style objects, self-closing tags and camelCase.
  • CSS Gradient Generator — Design linear, radial and conic CSS gradients with live color stops and copy the code.
  • CSS Box Shadow Generator — Build layered CSS box-shadow values with a live preview and copyable code.
  • CSS Border Radius Generator — Create simple or per-corner CSS border-radius, including blob shapes, with a live preview.
  • .editorconfig Generator — Generate an .editorconfig from indent, charset and newline options with per-language overrides.
  • Aspect Ratio Calculator — Simplify ratios, solve missing dimensions and fit sizes into boxes, with CSS output.
  • Color Palette Generator — Generate harmonious color palettes: lock colors, pick a harmony, copy HEX and export CSS, Tailwind or JSON.

Network

  • CIDR / Subnet Calculator — Calculate network, broadcast, host range and mask from a CIDR block.
  • IPv6 ↔ IPv4 Converter — Convert between IPv4 and IPv6 (mapped/expanded/compressed) and extract embedded IPv4.
  • User Agent Parser — Parse a User-Agent string into browser, engine, operating system and device, in your browser.
  • HAR File Viewer — Open a HAR file and inspect the request waterfall, headers, timings and sizes, in your browser.
  • IP Range to CIDR — Convert a start and end IP address into the minimal set of CIDR blocks, and back.
  • Set-Cookie Parser — Parse Set-Cookie and Cookie headers into a readable table of names, values and attributes.
  • IP Address to Integer Converter — Convert an IPv4 or IPv6 address to its integer, hex and binary form, and back.
  • MAC Address Generator — Generate random or vendor-prefixed MAC addresses in several formats.
  • WiFi QR Code Generator — Create a scannable QR code that joins a WiFi network, with correct escaping.
  • Download Time Calculator — Estimate how long a file takes to transfer at a given connection speed.
  • DMARC Record Generator — Build and validate a DMARC DNS TXT record with policy, reporting and alignment.
  • SPF Record Generator — Build and validate the SPF TXT record that stops others sending mail as your domain.
  • Port Number Lookup — What runs on a TCP or UDP port — search by number or service name.
  • Data Usage Calculator — Turn streaming, browsing and call habits into monthly gigabytes and cap forecasts.
  • DKIM Record Generator — Build and inspect the DKIM TXT record that publishes your mail signing key.
  • MTU & MSS Calculator — Work out TCP MSS from an MTU, allowing for IPv6, tunnels and TCP options.
  • Reverse DNS Generator — Turn IPs and prefixes into PTR names, zone files and RFC 2317 delegations.
  • CAA Record Generator — Build the DNS record that names which certificate authorities may issue for your domain.
  • SRV Record Generator — Build and decode SRV records for SIP, XMPP, Minecraft, LDAP and Autodiscover.
  • WHOIS Record Parser — Turn a raw WHOIS response into dates, registrar, name servers and decoded status codes.
  • Subnet Splitter — Split a CIDR block into equal subnets or size them by host count with VLSM.
  • DNS TXT Record Splitter — Split a long TXT value into 255-byte strings for DKIM, SPF and verification.
  • P2P File Transfer — Send files straight from one browser to another over a direct connection.

API Tools

  • cURL to Fetch — Convert a curl command to a JavaScript fetch() call.
  • URL Parser — Break a URL into its parts and list query parameters.
  • API Request Client — Send HTTP requests, build headers and params, inspect responses — your last 25 requests are saved locally.
  • URL Builder & UTM Generator — Construct and validate fully encoded production URLs with standard analytics query flags (UTM) or custom query arrays.
  • OpenAI API Tester — Build, run and copy OpenAI Chat Completions API requests as cURL, Python and JavaScript.
  • Anthropic Claude API Tester — Build, run and copy Anthropic Claude Messages API requests as cURL, Python and JavaScript.
  • Google Gemini API Tester — Build, run and copy Google Gemini generateContent API requests as cURL, Python and JavaScript.
  • Replicate API Tester — Build, run and copy Replicate prediction API requests as cURL, Python and JavaScript.
  • Hugging Face API Tester — Build, run and copy Hugging Face Inference API requests as cURL, Python and JavaScript.
  • cURL to Python — Convert a curl command to Python requests code.
  • cURL to Go — Convert a curl command to Go net/http code.
  • cURL to PHP — Convert a curl command to PHP cURL code.
  • cURL to Node.js (axios) — Convert a curl command to Node.js axios code.
  • Token Counter — Count tokens for GPT, Claude and Gemini live — exact OpenAI counts plus Claude/Gemini estimates.
  • LLM API Cost Calculator — Estimate GPT, Claude and Gemini API costs from token counts, with custom price overrides.
  • cURL to Rust — Convert a curl command to Rust reqwest code.
  • HAR to cURL — Turn requests from a browser HAR file into runnable cURL commands, with secrets stripped.
  • Postman to cURL — Turn a Postman collection export into runnable cURL commands, variables resolved.
  • cURL to C# — Convert a curl command to C# HttpClient code.
  • cURL to Java — Convert a curl command to Java 11 HttpClient code.
  • cURL to Ruby — Convert a curl command to Ruby Net::HTTP code.
  • cURL to PowerShell — Convert a curl command to PowerShell Invoke-RestMethod.
  • cURL to Swift — Turn a curl command into Swift code that uses URLSession.
  • cURL to Dart — Turn a curl command into Dart code for Flutter using package:http.

Security

  • JWT Decoder — Decode JWT header & payload and inspect exp / iat (no verification).
  • Hash Generator — SHA-256 / SHA-1 / SHA-384 / SHA-512 via the Web Crypto API.
  • Password Generator — Generate strong, random passwords with a strength meter (crypto-secure).
  • SSH Key Generator — Generate Ed25519, RSA or ECDSA SSH keypairs in your browser and download the public and private keys.
  • PPK ↔ PEM Converter — Convert SSH private keys between PuTTY .ppk and OpenSSH/PEM (RSA & Ed25519) — locally in your browser.
  • TOTP / 2FA Generator — Generate time-based one-time passwords (2FA codes) from a base32 secret.
  • JWT Signer — Create and sign a JWT (HS256/384/512) from a payload and secret — Web Crypto.
  • Basic Auth Generator — Generate and decode HTTP Basic Auth Authorization headers from a username and password.
  • Certificate & Private Key Matcher — Confirm an X.509 certificate or CSR and a private key belong together (the classic modulus mismatch check) — locally in your browser.
  • PFX to PEM Extractor — Open a password-protected .pfx/.p12 file and split it into certificate, chain, and private-key PEM blocks.
  • Bcrypt Generator — Hash a password with bcrypt and verify a password against a bcrypt hash, in your browser.
  • HMAC Generator — Generate an HMAC (SHA-256, SHA-1, SHA-512) from a message and secret key using Web Crypto.
  • Password Strength Checker — Check password strength with entropy, character-set and common-pattern analysis, in your browser.
  • X.509 Certificate Decoder — Decode a PEM or DER certificate to view subject, issuer, validity, SANs and fingerprints.
  • Diceware Passphrase Generator — Generate a memorable, high-entropy passphrase from the EFF word list, in your browser.
  • CSP Analyzer — Parse a Content-Security-Policy header into a directive table with warnings and explanations.
  • File Hash Checksum — Compute MD5, SHA-1, SHA-256 and SHA-512 checksums of files and compare against an expected hash.
  • IBAN Generator & Validator — Generate valid test IBANs by country and validate any IBAN with MOD-97 check digits.
  • AES Encrypt / Decrypt — Encrypt and decrypt text with AES-GCM and a passphrase, using Web Crypto in your browser.
  • SHA-3 & Keccak Hash Generator — Hash text or hex with SHA-3, Keccak-256 and SHAKE, for Ethereum and general use.
  • MD5 Hash Generator — Generate an MD5 hash of text or a file, in your browser.
  • CRC32 Checksum Calculator — Compute a CRC32 checksum of text as hex and decimal, in your browser.
  • CSR Decoder — Read a certificate signing request: subject, SANs, key size and signature check.
  • PDF Privacy Scanner — Find the metadata and personal data hiding inside a PDF.
  • Auto-Redact PDF — Find emails, phone numbers, card and ID numbers across a PDF and black them out.
  • Remove PDF Restrictions — See which actions a PDF blocks and lift the permission flags on a file you own.
  • PDF Sanitizer — Remove JavaScript, auto-run actions, embedded files and other active content from a PDF.

Geo / Maps

  • Coordinate Map Viewer — Plot a latitude/longitude on an OpenStreetMap map, or click the map to read coordinates back out.
  • GPX to GeoJSON — Convert GPX to GeoJSON and back — GPS tracks, routes and waypoints to GeoJSON features, or GeoJSON back to a GPX file.
  • KML to GeoJSON — Convert KML ⇄ GeoJSON — turn Google Earth KML into GeoJSON for web maps, or GeoJSON back into KML.
  • WKT to GeoJSON — Convert WKT (Well-Known Text) to GeoJSON and back, in your browser.
  • GeoJSON to CSV — Convert a GeoJSON FeatureCollection to CSV and back — Point features become latitude/longitude columns with their properties.
  • Plus Codes Converter — Convert between latitude/longitude and a Plus Code (Open Location Code) both ways, with the covered bounding box and cell size.
  • MGRS Converter — Convert between latitude/longitude and MGRS (Military Grid Reference System) coordinates, both ways, in your browser.
  • Distance Between Coordinates — Measure the great-circle distance between two latitude/longitude points in km, miles and nautical miles, with bearing and a map.
  • GPX Viewer — Open a GPX file and see its tracks, routes and waypoints on a map, with distance, elevation and bounds.
  • Coordinate Converter (DMS & Decimal) — Convert coordinates between decimal degrees, DMS and degrees-decimal-minutes, both ways, in your browser.
  • Geohash Converter — Encode latitude/longitude to a geohash and decode a geohash back to coordinates, with bounding box and neighbors.
  • Polyline Encoder & Decoder — Encode coordinates to a Google encoded polyline string and decode polylines back to coordinates or GeoJSON.
  • GeoJSON Viewer & Validator — Paste or drop GeoJSON to validate it and see its features on a map, with feature counts and a bounding box.
  • UTM Converter — Convert between latitude/longitude and UTM coordinates (zone, hemisphere, easting, northing) on the WGS84 ellipsoid.
  • GeoJSON Bounding Box — Get the bounding box, centre, area and length of any GeoJSON, in both coordinate orders.
  • GeoJSON Simplify — Thin dense GeoJSON lines and polygons with Douglas–Peucker at a metre tolerance.
  • Map Tile Calculator — Convert between coordinates, XYZ tiles, TMS and quadkeys, with tile counts.
  • NMEA Parser — Decode GPS NMEA sentences into coordinates, speed and GeoJSON, checksums included.
  • Maidenhead Grid Square Converter — Convert coordinates to a Maidenhead locator and back, with distance and beam heading.
  • Geographic Midpoint Calculator — Find the true midpoint of two or more coordinates, with optional weights.
  • Point in Polygon Checker — Test whether coordinates fall inside a GeoJSON polygon, with holes handled.
  • Web Mercator Converter — Convert WGS84 latitude and longitude to EPSG:3857 metres, and back.
  • Country Code Lookup — Search ISO 3166-1 alpha-2, alpha-3, numeric, dialling codes and ccTLDs.

Programmatic Ads

AI & Agents

Online Tests

  • Typing Speed Test — Measure your typing speed in WPM with accuracy, consistency and a per-second chart.
  • Click Speed Test (CPS) — Click as fast as you can and see your clicks per second over 1 to 60 seconds.
  • Reaction Time Test — Click the moment the screen turns green and see your average reaction time in milliseconds.
  • Keyboard Tester — Press any key to light it up on an on-screen keyboard — find dead keys and test rollover.
  • Mic Test — Check that your microphone works with a live level meter, waveform and a record-and-play-back check.
  • Webcam Test — Check your camera with a live preview, true resolution, frame rate and a snapshot.
  • Internet Speed Test — Measure your download speed, upload speed, ping and jitter, and see what your connection can handle.
  • Gamepad Tester — Test controller buttons, sticks and triggers, check stick drift and try vibration, live in your browser.
  • Dead Pixel Test — Check your screen for dead or stuck pixels with full-screen colors and patterns, and measure the refresh rate.
  • Speaker & Headphone Test — Test left and right speakers or headphones with stereo tones, a frequency sweep, bass and noise.
  • Color Blind Test — Check your color vision with Ishihara-style dot plates and get a plain-language result.

Music

  • Metronome — A steady click from 20 to 300 BPM with time signatures, subdivisions, accents and tap tempo.
  • Guitar Tuner — Tune a guitar, bass, ukulele or violin with your microphone or by ear, with chromatic mode and presets.
  • Virtual Piano — Play a piano keyboard with mouse, touch or computer keys, with sustain, several sounds, recording and MIDI export.
  • BPM Counter — Tap a beat to find its BPM, or analyze an audio file to detect the tempo of a song.
  • Tone Generator — Generate sine, square, sawtooth and triangle tones from 1 Hz to 20 kHz, with sweeps and left or right channel control.

Finance

Health & Fitness

Math

Science

Construction

  • Concrete Calculator — Estimate concrete volume and bags for slabs, footings and columns.
  • BTU Calculator — Estimate the BTU capacity needed to heat or cool a room.
  • Square Footage Calculator — Calculate area in square feet or meters for rooms and projects, with cost.
  • Stair Calculator — Calculate stair rise, run, number of steps and stringer length to code.
  • Roofing Calculator — Estimate roof area, squares and shingle bundles from footprint and pitch.
  • Tile Calculator — Calculate how many tiles and boxes you need for a floor or wall.
  • Mulch Calculator — Estimate mulch volume in cubic yards and bags for a bed and depth.
  • Gravel Calculator — Estimate gravel volume and weight in tons for an area and depth.
  • Paint Calculator — Work out how much paint a room needs from its size, coats, doors and windows.
  • Brick Calculator — Estimate bricks and mortar for a wall from its size, brick type and joint width.
  • Board Foot Calculator — Calculate board feet and lumber cost for a cut list of boards.
  • Drywall Calculator — Estimate drywall sheets, joint compound, tape and screws for a room.
  • Wallpaper Calculator — Rolls needed from wall size, roll size and pattern repeat, the way decorators count.
  • Fence Calculator — Posts, rails, pickets and concrete bags for a fence run, using the fencepost rule.
  • Rebar Calculator — Count the bars, laps, ties and weight of reinforcement for a concrete slab.
  • Asphalt Calculator — Turn a driveway or car park into tons of hot mix, cubic yards and cost.
  • Insulation R-Value Calculator — Add up an assembly’s R-value, U-factor and heat loss layer by layer.
  • Deck Calculator — Boards, joists, footings and screws for a deck, with joist spans checked.
  • Stud Calculator — Count studs, plates, headers and cripples for a wall, openings included.
  • Roof Pitch Calculator — Convert pitch, angle, grade and slope factor, with rafter lengths and roof area.
  • Pipe Volume Calculator — Volume, water weight, fill time and flow velocity for any pipe run.
  • Siding Calculator — Squares, boxes, boards or panels of siding from wall sizes, gables and openings.

Automotive

Everyday

  • GPA Calculator — Calculate your grade point average from course grades and credit hours.
  • Grade Calculator — Compute a weighted course grade and the score needed on the final exam.
  • Sleep Calculator — Find the best bedtimes or wake times based on 90-minute sleep cycles.
  • Golf Handicap Calculator — Estimate a golf handicap index from your recent scores and course data.
  • Dice Roller — Roll any number and type of dice (d4–d20) with modifiers and totals.
  • Shoe Size Converter — Convert shoe sizes between US, UK, EU and centimeters for men and women.
  • Bra Size Calculator — Estimate your bra size from band and bust measurements in US, UK and EU.
  • Unit Conversion Calculator — Convert length, weight, temperature, volume, area, speed and more.
  • Height Calculator — Convert height between feet/inches and cm, and predict a child’s adult height.
  • Cooking Measurement Converter — Convert cups, spoons, millilitres, grams and ounces using ingredient density.
  • Pet Age Calculator — Convert dog and cat years to human years using size-adjusted ageing curves.
  • Ring Size Converter — Convert ring sizes between US, UK, EU, Japan, diameter and circumference.
  • Clothing Size Converter — Convert women’s and men’s clothing sizes between US, UK, EU, Italian and French charts.
  • Unit Price Calculator — Compare pack sizes by price per 100 g, 100 ml or piece and spot the real bargain.
  • Chinese Zodiac Calculator — Your animal sign and element from your birth date, honouring Chinese New Year cutoffs.
  • Recipe Scaler — Scale any recipe by servings, a multiplier or a change of pan size.
  • Random Name Picker — Draw winners, shuffle a list or split teams, with a seed you can share.
  • Coffee Ratio Calculator — Solve coffee, water or ratio for any brew method, in grams and cups.
  • Hat Size Converter — Convert head circumference to US, UK, EU and S/M/L hat sizes.
  • Pizza Size Calculator — Compare pizzas by area and price per square inch, and size an order for a group.
  • TV Size Calculator — Screen width, height, area and the right viewing distance for any diagonal.
  • Mattress Size Converter — Match US, UK, European and Australian bed sizes, and check they fit the room.
  • Secret Santa Generator — Draw Secret Santa names with couple and past-match exclusions, then hand out matches by passing the device or private links.
  • Spin the Wheel — Add names or options, spin a colorful wheel and let chance pick the winner, with weights, sound and history.

Online developer tools without the privacy risk

Most online utilities make you paste sensitive data, upload files or process private content on remote servers. ArrayKit is designed for developers, QA, DevOps, support and technical teams who need fast tools for JSON, PDFs, images, API debugging, encoding, security checks and formatting — with a privacy-first, browser-based approach.

Frequently asked questions

Can I use ArrayKit tools right away?
Yes. The core browser-based tools are available online and you can start using them instantly, right in your browser, with nothing to install.
Do I need an account to use ArrayKit?
You can use the core browser-based tools right away. Optional account features are planned for saved preferences, favorites, history and team workflows.
Does ArrayKit upload my files or text?
ArrayKit is built around browser-based processing: tools run locally on your device, so your content does not need to be uploaded to a server.
Who is ArrayKit for?
Developers, QA engineers, DevOps and support teams, data analysts — anyone who works with JSON, PDFs, images, APIs, text, encoders, formatters or security utilities.
Can I use ArrayKit for sensitive data?
ArrayKit is privacy-first and processes data in your browser, but you should still avoid pasting production secrets, private keys or passwords into any online tool unless you have verified how it works.
Do the tools work offline?
Once a tool’s page and assets have loaded, it can keep working offline, depending on your browser’s caching and the specific tool.