✨ Chaos Lab Toolbox

Merge multiple PDF files in sequence, all processed locally in browser

Convert images to PDF with custom scaling, page size and margins

Render PDF pages as high-res PNG images, local processing

Extract PDF pages by range, or split every N pages into separate files

Add text watermarks to PDF with Chinese support, tile/center, opacity

Rotate or delete PDF pages and export, processed locally

Swap ID photo backgrounds: blue/white/red/transparent with tolerance

Crop to standard ID photo sizes with 6-inch print layout generation

Generate QR codes from text or URLs with adjustable size

Compress JPG/PNG/WebP locally, adjustable quality and max width

Convert image to Base64 Data URL for inline embedding

Add text watermarks to images with tile/position, opacity, rotation and local processing

Batch convert between PNG/JPEG/WebP formats locally

Upload or paste a QR code image to extract its content (link/text), decoded locally without uploading

Multi-pass compression + color filters + noise to turn any image into a classic deep-fried meme

Convert images to classic 8-bit pixel art with adjustable resolution and color count

Resize images with locked ratio, export as PNG or JPEG

Cut images into 3×3/4×4/5×5 grids and download all slices in one click

Extract every frame of an animated GIF and export as PNG, decoded locally without uploading

12 one-click preset filters: black & white, classic, cinematic, cool tone, invert and more, processed locally

Read photo metadata: camera parameters, date taken and GPS location, parsed locally without uploading

Pick color from any image position, get HEX/RGB values and palette

Convert between HEX/RGB/HSL colors with live preview sliders

Generate 20+ barcode formats including CODE128, EAN13 and UPC, downloadable as PNG

Merge multiple images horizontally or vertically into a long image, with spacing and background color options

Hide text in image pixels (LSB) with optional password, invisible to the eye

Generate placeholder images with custom size, color and text

Explore classic Chinese traditional colors with HEX, RGB, CMYK values

36 curated CSS gradients, one-click copy, great for web and poster design

Visual multi-layer CSS gradient editor with live preview and random inspiration

Color harmony generator based on complementary, triadic, analogous schemes

Explore Japanese traditional Washoku colors with HEX, RGB, CMYK values

Check text/background color contrast against WCAG accessibility standards

MP3/AAC/FLAC/WAV/OGG/M4A conversion via FFmpeg command generator with tutorial

Trim audio clips locally with fade in/out, export as WAV

Text-to-speech with adjustable speed and pitch for reading aloud

Adjust audio volume and export, supports extracting audio from video

Record microphone audio locally, requires mic permission

Merge multiple audio files in sequence with configurable gap, export WAV

Format convert, remux, mute, rotate, flip, reverse, speed change, watermark via FFmpeg

Compress video to target size with auto-calculated bitrate via FFmpeg

Generate high-quality GIF from video using 2-pass palette method via FFmpeg

Play video and capture any frame as HD PNG locally

Record screen/window/tab with optional system audio, saved locally

View video duration, resolution, size, format info locally

Aggregate trending topics from Weibo, Zhihu, Bilibili, Douyin, Baidu

Generate 12+ chart types online and export as HD PNG

Extract ZIP files locally and download individually; see notes for RAR/7Z

Package multiple files into ZIP archive locally in browser

4 methods to convert Office docs to PDF: Office, WPS, LibreOffice CLI

Master format conversion guide for documents, images, audio, video, archives, ebooks

Batch extract all images from Office documents locally

Fix garbled text files by auto-detecting GBK/Big5/UTF-8 encoding

EPUB/MOBI/AZW3/PDF/TXT conversion via Calibre with install tutorial

Convert SRT, VTT and ASS subtitle formats with automatic timeline adjustment, processed locally

Shift SRT subtitle timing forward or backward to sync with video

Count characters, words, lines, paragraphs & UTF-8 bytes

Convert text to bold, italic, script, gothic, circled and other fancy Unicode fonts

Live Markdown preview supporting headings, lists, code blocks, and quotes

Remove duplicate lines with options for case, blank lines, and order

Convert to upper/lower/capitalized/sentence case or swap

Diff two text blocks line by line, red for removed, green for added

Line operations: sort, reverse, number, shuffle, deduplicate, extract columns

Extract all email addresses from text with auto-deduplication

Extract Chinese mobile numbers from text, supports +86 prefix

Hide encrypted info in text using zero-width characters with password protection

Generate Chinese or English Lorem Ipsum text for layout testing

Extract HTTP/HTTPS URLs from text with auto-deduplication

Add line numbers with customizable format and start value

Convert to superscript/subscript for chemistry, math, fancy nicknames

Reverse text by characters, words, lines, or per line

Convert units across 7 categories: length, weight, temperature, area, volume, speed, data

Compare equal payment vs equal principal mortgage plans

Real-time exchange rates for 30+ currencies from ECB and open APIs

Calculate BMI with Chinese standard weight classification

Web calculator with arithmetic, parentheses, percentage, keyboard support

Calculate exact age, days to next birthday, zodiac and Chinese zodiac

Calculate percentage, ratio, and growth rate instantly

Convert between binary, octal, decimal, hex, and base 2-36 with BigInt

Calculate days between dates or add/subtract N days from a date

Customizable countdown timer with presets and alarm sound

Stopwatch with centisecond precision, lap and split timing

Standard Pomodoro timer: 25min focus + 5min break

View current time in 10 major cities with live second refresh

Monthly calendar with today/weekend highlighting and quick navigation

CSV table to JSON array with custom delimiters

Number to Chinese RMB (yuan/jiao/fen) or plain Chinese digits

Convert JSON arrays to CSV with auto field extraction

Markdown to HTML with source and preview views

Convert between camelCase, PascalCase, snake_case, kebab-case etc.

Convert between fullwidth and halfwidth characters

Generate cryptographically secure passwords with custom length and charset

Compute MD5 hash online, supports 32-bit upper/lower and 16-bit formats

Check password strength, entropy, crack time with improvement tips (local)

Compute SHA-1/256/384/512 and CRC32 hash values online

Online AES symmetric encryption and decryption with CBC/ECB modes

Generate random integers in range with dedup, sort, and batch options

Convert text to/from Morse code with full alphabet and punctuation support

Validate Chinese ID card and query province, birthday, age, gender, zodiac

Look up retirement age under gradual delayed retirement policy by birth date

Local todo manager with completion tracking, filters, and localStorage

Random cuisine picker to solve food indecision, supports re-pick

Random witty poison chicken soup quotes, copy and share

Tap for merit +1 with sound effect and floating animation, saved locally

Spin yes/no wheel for quick random binary decisions

Predict possible and impossible child blood types from parents (with Rh)

Predict child hereditary target height calculated separately for boys/girls

Visualize 80 years as 4000 grid cells to feel time passing

Measure reaction time over 5 rounds with best and average stats

Common emoji collection, click to copy, browse by category

Scrolling teleprompter for video recording with speed, fullscreen, mirror

1-minute Chinese typing speed test with real-time WPM and accuracy

Real-time keyboard tester for key response, ghosting, and n-key rollover

Random name picker with multi-draw and removal, great for classrooms

Dead pixel, backlight bleed, grayscale, and solid color screen test

Generate random Chinese male/female names for novels, tests, placeholders

Roll up to 6 dice with animation and total score

Prevent screen sleep for recipes, navigation, livestreams

Chinese dynasties timeline from Xia to Republic of China

Calculate baby's 100th day: date, weekday, and countdown

Online sketchpad with custom brush, eraser, and PNG export

Calculate expiry date and remaining shelf life for food and cosmetics

Quick scoreboard for sports/games with large display, side swap, reset

Flip a coin with flip animation and heads/tails statistics

Validate, pretty-print or minify JSON with error line:col reporting

Convert Unix timestamps to dates, auto-detect seconds/milliseconds

Convert text to/from Base64, handles Unicode correctly, URL-safe mode

URL encode/decode supporting both component and full URI modes

Online regex tester with group highlighting and match details

Batch generate UUID v4 unique IDs using cryptographic random

Convert between Chinese and Unicode escape sequences for config files

Decode JWT tokens to view header, payload, signature, and expiry

Convert text to/from hexadecimal UTF-8 byte representation

Batch find/replace with regex, supports capture groups and all flags

Encode/decode HTML entities to prevent tag parsing

Quick reference table of common HTTP status codes with search

Remove comments and excess whitespace from JS/CSS/HTML

Visual email signature builder generating HTML for major email clients

Analyze keyword density for English words and Chinese bigrams for SEO

Parse URL into protocol, domain, path, query params, fragment with auto-decode

Visual robots.txt generator with one-click allow/disallow all

Generate SEO meta tags: title, description, keywords, and Open Graph

Parse User-Agent to identify browser, OS, engine, and device info