Free Online Tools, Right in Your Browser

Free online Base64 encoder and decoder with full UTF-8 support. Convert text to Base64 or decode Base64 back to plain text instantly.

Write Markdown with a live, sandboxed preview, then export clean HTML or the original .md source file for your notes. Your text stays in the browser.

Format, validate and minify JSON online. Pretty-print with 2 or 4 spaces, get precise error positions, and copy or download the result.

Run real SQLite queries in the browser: a demo database to explore, sample queries, and instant result tables. Powered by sql.js WASM.

Compute MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes for any text instantly, using the browser's Web Crypto API. Runs locally, so your text is never sent anywhere.

Generate cryptographically random passwords. Choose length and character sets, and exclude look-alike characters. Passwords are created locally and never stored.

Compress JPG, PNG and WebP images with a quality slider and optional resizing. No size limits. Photos stay in your browser.

Generate QR codes for URLs, text or any content. Customize size, colors and error correction, then download a crisp PNG. Static codes never expire.

Convert colors between HEX, RGB, HSL and HSV with a live preview. Pick a color or paste any CSS color value and copy the format you need.

Free online Base64 encoder and decoder with full UTF-8 support. Convert text to Base64 or decode Base64 back to plain text instantly.

Free online URL encoder and decoder. Percent-encode query parameters or encode complete URLs while preserving their structure.

Count words, characters, sentences and paragraphs in real time as you type. CJK-aware word counting and a reading-time estimate included.

Convert text between UPPERCASE, lowercase, Title Case, Sentence case, camelCase, PascalCase, snake_case and kebab-case in one click.

Test JavaScript regular expressions live. See every match highlighted with capture groups, match indexes and instant syntax errors.

Write Markdown with a live, sandboxed preview, then export clean HTML or the original .md source file for your notes. Your text stays in the browser.

Fix garbled Chinese text caused by wrong encodings. Tries UTF-8, GBK, Big5 and Latin-1 round-trip combinations. Paste the garbled text and pick the likely encoding.

Convert Chinese text to Pinyin with or without tone marks, or to Zhuyin. Polyphonic characters are resolved by context. Results appear as you type.

Generate Lorem Ipsum paragraphs, sentences or words for design mockups — with or without the classic opening. Free and instant.

Convert Markdown to a print-styled document and save it as PDF through the browser print dialog — selectable text, crisp fonts.

Compare two texts line by line and see additions and deletions highlighted, with add/remove counters. Ignore case or edge whitespace when comparing.

Convert Chinese text between Simplified and Traditional, including Taiwan and Hong Kong variants with their local vocabulary (软件 → 軟體).

Chain line operations such as dedupe, sort, trim, renumber and shuffle, with live counts and one-step undo. Every step is reversible with undo.

Generate printable practice sheets: 米字格, 田字格, plain squares and English ruled lines. Export a vector PDF with chosen cell size.

Format, validate and minify JSON online. Pretty-print with 2 or 4 spaces, get precise error positions, and copy or download the result.

Generate random UUID v4 and time-ordered UUID v7 identifiers in bulk, using the browser cryptographic random API. Copy one or all with a click.

Convert Unix timestamps to readable dates and back. Shows local time, UTC and ISO 8601, handles both seconds and milliseconds, with a live current-time display.

Decode JWT header and payload into readable JSON, with expiry and issue dates shown in plain language. Nothing is sent to a server.

Parse and generate cron expressions online for Linux crontab, Spring @Scheduled and Quartz. Per-field breakdown, plain-language schedule and next run times.

Convert numbers between binary, octal, decimal, hex and any base from 2 to 36. Results update instantly as you type. Copy any representation with one click.

Parse any User-Agent string into browser, engine, OS, device and CPU details. Your own UA is pre-filled for a quick check.

Generate typed entity classes from JSON for TypeScript, Java, Go, C#, Python, Kotlin and Swift. Nested objects become separate classes.

Convert .xlsx files to CSV sheet by sheet, and turn CSV text or files back into Excel workbooks. Runs entirely in your browser.

Open huge log files of hundreds of megabytes, streamed in the browser, with level counts and keyword search. Logs never leave your device.

Run real SQLite queries in the browser: a demo database to explore, sample queries, and instant result tables. Powered by sql.js WASM.

Format, validate and minify XML with a collapsible tree: pretty-print with 2/4 spaces or tabs, jump to syntax errors by line and column, copy or download the result.

Format and validate YAML with a collapsible tree, jump to syntax errors by line and column, and export a compact flow-style view.

Beautify or minify CSS with a parser that keeps calc(), content strings and data URIs intact. Shows byte savings after each run.

Compute MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes for any text instantly, using the browser's Web Crypto API. Runs locally, so your text is never sent anywhere.

Generate cryptographically random passwords. Choose length and character sets, and exclude look-alike characters. Passwords are created locally and never stored.

Interactive demos of the birthday attack and brute-force search on truncated hashes. Hands-on and built for learning. Great for understanding why short hashes are weak.

Generate time-based one-time passwords from a Base32 secret or otpauth:// URI, with 6 or 8 digits and SHA-1, SHA-256 or SHA-512.

Drop files to compute MD5, SHA-1 and SHA-256 in one pass, then paste the published checksum to confirm a download is intact and untampered.

Compress JPG, PNG and WebP images with a quality slider and optional resizing. No size limits. Photos stay in your browser.

Generate QR codes for URLs, text or any content. Customize size, colors and error correction, then download a crisp PNG. Static codes never expire.

Draw a smooth handwritten signature with mouse, touch or stylus. Adjustable pen, undo, and transparent-background PNG export.

Add visible text watermarks (position/tile/opacity) and embed invisible LSB blind watermarks that can be extracted later.

Split an image into a 3×3 grid or any rows and columns for social feeds. Preview the tiles and download them all at once.

Stitch screenshots into one long image, vertically or horizontally, with adjustable gaps and background colour. Images keep the order you select.

Combine photos into one collage with 35 layouts, drag-to-swap cells, zoom and custom backgrounds. Export PNG or JPEG up to 3072 px.

Read EXIF metadata and GPS coordinates from photos, including camera, lens and exposure settings, with map links. Runs locally.

Turn any image into a complete favicon set: 16-256px PNGs, a multi-resolution .ico file, Apple touch icon and ready-to-paste HTML.

Rasterize SVG to PNG at any scale, or render long text into a styled PNG image. Perfect for code screenshots and share cards.

Turn a clip of MP4 or WebM video into an animated GIF. Choose start, duration, frame rate and size. The video is never uploaded.

See the colors of any image as an interactive 3D point cloud in RGB space. Drag to rotate, scroll to zoom. Rendered with Three.js.

Read a QR code from an image by uploading, dropping or pasting a screenshot. Decodes URLs, Wi-Fi and vCard payloads. Paste a screenshot straight from the clipboard.

Crop images with a draggable selection and ratio presets such as 1:1, 4:3 and 16:9. Export PNG or JPEG at exact pixel size.

Combine a batch of images into one PDF in your chosen order, with A4 pages or pages that fit each image. Runs locally. Pages follow the order you choose.

Convert images between PNG, JPG and WebP right in your browser. Batch convert many files, set JPEG or WebP quality, and download. Nothing is uploaded.

Convert iPhone HEIC photos to JPG or PNG right in your browser. Batch convert many files and set the JPEG quality. Nothing is uploaded.

Convert colors between HEX, RGB, HSL and HSV with a live preview. Pick a color or paste any CSS color value and copy the format you need.

Convert font sizes between px, pt, em, rem and %, with a Chinese type-size reference table. Live results as you type. Useful when translating design specs between units.

Build linear or radial CSS gradients visually: drag angle and colour stops, use presets, then copy the CSS or download the gradient as a PNG.

Check the WCAG contrast ratio between text and background colours, with AA/AAA verdicts for normal and large text plus a live preview.

Calculate network and broadcast address, subnet and wildcard masks, usable host range and address type from an IPv4 CIDR, and split the network into equal subnets.

Pick a base colour to get complementary, triadic, analogous and monochromatic schemes, plus a tint-to-shade ramp and CSS export.

Build a valid robots.txt file with user-agent rules, allow and disallow paths, crawl delay and sitemap URLs. Copy or download the result.

Precise online stopwatch with lap times, plus a live world clock: analog dials for major cities with digital readouts and UTC offsets below.

Test every key on your keyboard online. See key codes, modifier states and a rolling press log. Nothing to install, and nothing is recorded.

Test mouse buttons, wheel and tracking online. Live coordinates, click counters per button and a movement trail on canvas.

Fullscreen pure-color tests to find dead pixels and check uniformity, plus screen info: resolution, pixel ratio and color depth.

Calculate BMI (WHO/CN categories), body fat percentage (U.S. Navy tape method) and basal metabolic rate (Mifflin-St Jeor) with daily calorie needs.

Play white, pink or brown noise and pure-tone sound waves for sleep, focus or tinnitus relief. Generated live by Web Audio.

Mortgage calculator for commercial, housing-fund and mixed loans: monthly payment, total interest and a per-part breakdown.

Turn any image into a playable jigsaw puzzle from 3×3 to 5×5, with a timer and move counter. Click two tiles to swap. Restore the original picture to win.

Play a two-octave piano with your computer keys, mouse or a real MIDI keyboard. Web Audio synthesis with selectable waveforms.

Draw a floor plan with grid-snapped walls, automatic dimensions, doors, windows and PNG export in your browser. Great for quick layout sketches before a renovation.

Run as many countdowns as you need, each with its own name, duration and progress ring. A triple beep sounds at zero. Presets such as 5 or 25 minutes add in one click.

Convert between units of length, weight, area, volume, temperature, speed, data storage and time — with an instant table of the value in every unit of the category.

Merge several PDFs in any order, extract a page range into a new file, delete pages, or rotate every page by 90/180/270 — files never leave the page.

Find the gap between two dates in years, months, days or weekdays, add or subtract time, and turn a birthday into an age.

Check your camera and microphone with a live preview, resolution readout, mic level meter, device switching and PNG snapshot.

Record a screen, window or browser tab with optional system and microphone audio, pause and resume, then download a WebM file.