All-in-one Online Tools

Visual Cron builder: pick minute-hour-day-month-weekday fields and preview next run times live.

JSON beautify, minify and validate with auto error location for missing brackets and stray commas.

Convert Unix timestamps to dates and back with second/millisecond precision and live current time.

Test regex with live match highlighting, capture groups and substitution, toggling g/i/m/s flags.

Split a JWT into header, payload and signature, then base64url-decode claims and expiry without a key.

Issue JWTs with custom header, claims and expiry across HS256, RS256, ES256 for auth-flow testing.

Batch-generate v1, v4 and v5 UUIDs with or without hyphens for keys and distributed IDs.

Generate short, URL-safe NanoIDs with custom alphabet, length and count for keys and IDs.

Percent-encode and decode URLs, query strings and Chinese chars in two modes.

Split any URL into protocol, host, path and query, with params parsed to a key-value table.

Reverse text by character with full Unicode support for multi-line and very long strings.

Export JSON arrays to CSV, flattening nested fields for analysis in Excel.

Bidirectional JSON/YAML conversion that preserves indentation and arrays for K8s, Compose and CI configs.

Auto-generate TypeScript interface and type definitions from JSON, with nested, union and optional fields.

Compare two JSON structures, highlighting added, removed and changed fields by path, order-agnostic.

Beautify, minify and highlight SQL across MySQL, PostgreSQL, Oracle with keyword casing.

Convert HTML special characters to and from entities, named and numeric, to prevent injection.

General text diff with line-level add/delete highlighting, ignoring whitespace and case as needed.

Author flowcharts, sequence, Gantt and pie diagrams in Mermaid with live preview and SVG/PNG export.

Beautify, minify and validate XML, flagging unclosed tags and attribute errors for SOAP configs.

Normalize YAML indentation, minify and validate, catching indent errors and duplicate keys.

CSS beautify, minify and validate with consistent indentation and property order for cleaner styles.

JavaScript beautify, minify and syntax-validate with consistent style for dev and production.

Turn JS object literals into valid JSON in one click — handles single quotes, unquoted keys, trailing commas and comments, normalizing special values like undefined and NaN.

Prettier-based beautifier for JS, TS, Vue, HTML, CSS, JSON, YAML and 15+ languages to unify style.

Visual editor for .env files with grouping, type validation and multi-environment export.

Decode UA strings into browser, OS and device type (PC/phone/tablet) for compatibility checks.

Quick reference for 1xx-5xx status codes with meaning, scenario and troubleshooting hints.

Translate Cron expressions into plain-language descriptions to understand existing schedules.

Convert capacity across B/KB/MB/GB/TB, distinguishing binary and decimal standards with instant results.

Full ASCII reference searchable by char, decimal, hex and binary, with encoding conversion for debugging char

Test JSONPath expressions live against JSON, with filters and recursive descent to extract exact nodes.

Convert XML and JSON both ways, preserving attributes via @ and handling namespaces and CDATA.

Beautify, minify and validate TOML tables, keys and arrays for Cargo and Pelican configs.

Detailed meanings, values and browser behavior of common request and response headers as a reference.

Look up file extension to MIME type or reverse across 200+ formats for Nginx, CDN and upload config.

Git command quick reference covering commit, branch, rebase and undo with copyable examples.

Reference for metacharacters, quantifiers, groups, lookarounds and Unicode with common patterns.

Escape and unescape strings covering quotes, backslashes and Unicode for common programming languages.

Generate .gitignore by project type, covering deps, build output and editor caches to avoid bad commits.

Visually design JSON structures and generate sample data plus OpenAPI Schema to align API contracts.

Parse PHP serialize strings into a readable tree of object properties and array depth for debugging.

Beautify and parse .proto IDL, validating messages and enums and showing field numbers and types.

Beautify and validate GraphQL queries with consistent indentation for easier API debugging.

Generate Lorem Ipsum with custom length plus fake names, emails and addresses for mock layouts.

Visually build Nginx server blocks with reverse proxy, HTTPS, load balancing and Gzip templates.

Visually orchestrate multi-container services into docker-compose.yml with ports and dependencies.

Generate RSA/Ed25519 SSH key pairs locally with passphrase and authorized_keys/config snippets.

Debug WebSocket connections with custom URL, headers, subprotocols and a full message log.

Lightweight REST API debugger with custom methods, headers, auth and body, showing status, timing and

Visually build and send HTTP requests with method, headers, params and auth, viewing full response.

Generate JSON Schema from a JSON sample, inferring types and constraints for validation and docs.

Count lines, characters, words and comment ratio by language to quantify project size and quality.

Manage CSS custom properties visually and generate :root variables and theming code for design tokens.

Pick colors visually and convert between HEX, RGB and HSL with palettes and history for frontend work.

Render regex as a railroad diagram showing quantifiers, classes and capture groups and backtracking.

Convert bitrate, bandwidth and storage units with binary/decimal care for capacity planning.

Generate structured mock data from API field definitions with custom status codes, latency and error branches

Side-by-side highlighted diff with syntax coloring and line-level comparison to spot changes fast.

Extract H1-H6 headings into an anchored TOC with GitHub/Hexo rules, ready to paste into READMEs.

Parse OpenAPI 3/Swagger 2 docs by tag and fire try-it-out requests, no local Swagger UI.

Compare MIT, Apache, GPL, LGPL and MPL on commercial, modification and redistribution terms.

Compare two semantic versions, bump major/minor/patch and parse prerelease and build metadata.

Show codepoint, UTF-8/UTF-16 bytes, block and category for any character, or search by name.

Quickly generate common code templates for components, hooks, config and script scaffolds to cut boilerplate.

Render PlantUML sequence, class, use-case and component diagrams live with PNG/SVG export.

Measure cyclomatic complexity, nesting depth and maintainability to spot risky code for refactoring and

Detect text or file encoding such as UTF-8, GBK and ISO-8859, helping debug mojibake and transcoding.

Measure FCP, LCP, CLS, TTFB and INP, graded Good/Needs Improvement/Poor to find bottlenecks.

Parse Git commit history into a categorized changelog following semantic commit conventions, with custom

Visually define grid rows, columns and gaps, then generate CSS Grid layout code with preview.

Visually build linear, radial and conic gradients with draggable stops, angle and live preview.

Visually stack multi-layer box-shadows, tuning offset, blur and color with live code output.

Paste or upload CSV to preview as a table, infer column types and convert to JSON for data checks.

IPv4 CIDR subnetting: network and broadcast addresses plus usable host range from an IP and prefix.

Two-way lookup of port numbers and services (HTTP, MySQL, Redis, DNS) with protocol notes.

Generate multi-stage Dockerfiles per language, tuned for image size and layer caching.

Paste JSON to generate Go structs with json tags, nested types and omitempty — skip hand-writing model fields.

Generate Java POJO classes from JSON with Jackson, Gson or Lombok for Spring Boot.

Convert JSON into Rust serde structs with inferred Option, Vec and HashMap types plus derive macros.

Infer Python types from JSON into dataclass, TypedDict or Pydantic BaseModel.

Generate Swift Codable structs from JSON with inferred Optional, Array and CodingKeys mapping for iOS.

Convert JSON to C# model classes with inferred properties and types for .NET API binding.

Infer column types from JSON arrays to build CREATE TABLE and INSERT across MySQL, PostgreSQL, SQLite.

Generate Content-Security-Policy headers that restrict resource sources and mitigate XSS injection.

Generate CORS response headers with custom origin, methods and credentials to stop cross-origin errors.

One-click HSTS, X-Frame-Options, X-Content-Type-Options and Referrer-Policy with OWASP values.

Build K8s Deployment, Service, ConfigMap and Ingress YAML via a form with probes and resource limits.

Count character occurrences, percentage and ranking in text, with ignore-whitespace and case-insensitive

Generate 32-char MD5 digests for text and files to verify integrity and detect content changes locally.

MD5, SHA-1, SHA-256, SHA-512 digests for text and files in one pass for checksums.

Base64 encode/decode for text, UTF-8 and images, with Data URL output for inline embedding.

Encrypt/decrypt with AES, DES, 3DES, RC4 and SM4, configurable mode, padding, key and IV, fully client-side.

Generate RSA key pairs (1024-4096 bit), encrypt/decrypt and sign with PKCS#1 v1.5 or PSS, browser-side.

Generate OpenPGP keys, encrypt, decrypt and sign text or files with GnuPG-compatible ASCII-armored output.

Parse X.509 certificates and CSR, inspect ASN.1 structure and resolve OIDs without OpenSSL.

Convert UTF-8, UTF-16, GBK, Big5 and Hex to fix mojibake and cross-system text.

Escape Unicode to \u sequences, normalize to NFC/NFD/NFKC/NFKD and strip diacritics for i18n.

Encode/decode Punycode for IDN domains, Quoted-Printable for email and NetBIOS names.

Convert text to/from binary, octal, decimal and hex byte sequences for protocol debugging.

Convert integers between binary, octal, decimal, hex and any base 2-36, with big numbers and signed bits.

Convert single/double-precision floats to hex bit patterns, exposing sign, exponent and mantissa.

Convert 8421 BCD (packed/unpacked) to and from decimal for PLCs, meters and POS systems.

Create strong passwords via Web Crypto with adjustable length, character classes and exclusion rules.

Generate RFC 6238 TOTP codes with HMAC-SHA1/256/512 and custom period/digits, Google Authenticator compatible.

Compress and decompress Gzip, Deflate and Zlib, with before/after size comparison for debugging.

Caesar, ROT13, Affine and Rail Fence ciphers with custom keys for crypto teaching and CTF.

Encrypt/decrypt text with the Vigenère polyalphabetic cipher and a custom keyword for crypto-history and CTF.

SHA-3, SM3, BLAKE2b and RIPEMD-160 digests for text and files, with tunable length for signing and compliance.

Encrypt/decrypt bytes with a cycling-key XOR cipher, hex and UTF-8 I/O, for reversing, obfuscation and CTF.

Translate text to/from International Morse Code with audio playback and custom WPM for ham-radio training.

Bacon cipher steganography: map letters to 5-bit A/B sequences to hide messages in plain sight.

HMAC-MD5/SHA1/SHA256/SHA512 message authentication codes for API signing and integrity.

Estimate password entropy and crack time against GPU and rainbow-table attacks, flag weak patterns via zxcvbn.

Bcrypt password hashing with adjustable cost (4-31) and salt to defeat rainbow tables and brute force.

Convert hex and Base64 both ways with live UTF-8 preview for debugging crypto output.

Generate SM2 key pairs and encrypt/decrypt/sign per GM/T, built for Chinese-crypto compliance, device-local.

Base32 encode/decode per RFC 4648 and Crockford, omission-proof for OTP secrets and DNSSEC records.

Base58 encode/decode for Bitcoin and Ripple, ambiguity-free compact representation of wallet addresses.

Apply ROT5, ROT13, ROT18 and ROT47 shifts for instant text obfuscation and recovery, handy for CTF.

Count letter, bigram and trigram frequencies and Shannon entropy to break classical ciphers.

CRC-8/16/32 with selectable polynomial, init and presets like zlib, CCITT, Maxim for protocols.

Compute Sum8/16/32, Fletcher and Adler-32 checksums for firmware and legacy protocol integrity.

Generate 256-bit SM3 digests per GM/T 0004, the Chinese counterpart to SHA-256, for compliance.

Encrypt/decrypt with SM4 (GM/T 0002) in ECB, CBC, CFB, OFB and CTR modes with tunable key and IV.

Generate cryptographically secure random numbers, bytes, hex and Base64 for keys, salts and nonces.

Chain Base64, URL, Hex, UTF-8 and Gzip steps to encode/decode nested data in order.

Derive keys from passwords with PBKDF2 and HKDF, custom iterations, salt and length for E2EE and token setup.

Affine cipher encrypt/decrypt using y=ax+b mod 26, with custom coprime multiplier and shift for crypto labs.

Encrypt/decrypt with the Rail Fence transposition cipher, adjustable rails and zigzag visualization.

Sign and verify with RSA, ECDSA and Ed25519 for identity, anti-tamper and e-contracts.

Encrypt/decrypt with the Playfair 5x5 matrix digraph cipher, custom keyword, for classical crypto study.

Simulate the WWII Enigma machine with rotors, reflector and plugboard for crypto history.

Base85 encode/decode for ASCII85 and Z85, denser than Base64 for PDF and messaging data.

Generate password wordlists from masks, charsets, leetspeak and pattern combos for hashcat.

Validate passwords against NIST SP 800-63B and OWASP ASVS, scoring length, complexity and breach hits.

Convert RSA, EC and OKP keys between PEM and JWK, compatible with PKCS#1/PKCS#8/SPKI for cross-platform use.

Ed25519 Edwards-curve signatures: fast, short keys, used in SSH, JWT and blockchain.

Hybrid encryption: symmetrically encrypt data, wrap the key under RSA or SM2 for safe delivery.

Simulate RFC 3161 Time-Stamp Protocol responses and verify TSA tokens for PDF archival and e-signature audits.

Detect LSB steganography in PNG/BMP and uncover zero-width Unicode characters in text for CTF forensics.

Parse and verify X.509 chains, checking signatures, expiry, EKU and basic constraints.

Argon2id/2d/2i password hashing with tunable memory, iterations and parallelism to resist GPU cracking.

Shift letters by 13 (digits by 5) for reversible obfuscation, the Usenet spoiler convention, browser-side.

AES-128/192/256 symmetric encryption with CBC, GCM and CTR; custom key, IV and AAD for API protection.

Caesar shift cipher with adjustable 1-25 shift, encrypt and decrypt for crypto intro and CTF.

ChaCha20-Poly1305 AEAD stream cipher with auth tag, no hardware AES needed for mobile and TLS.

Verify JWT signatures with HS/RS/ES families, checking expiry, issuer and claims to debug auth failures.

Issue JWTs with HS256, RS256, ES256 and EdDSA, custom header, claims and expiry, signed on-device.

Estimate security strength of RSA, ECC, DSA and symmetric keys in bits, compare compliant key sizes.

AES-256-GCM file encryption with Argon2-derived key, local-only for secure cloud backup.

Calculate days between two dates

Calculate future or past date by hours, days or weeks

Convert Chinese RMB amount to uppercase

Countdown to important dates

Body Mass Index calculator

Currency exchange rate calculator for reference

Convert length, weight, area and other units

Exact age, days lived, next birthday countdown, zodiac signs

Compare time across multiple time zones

Convert time between different time zones

Online stopwatch and countdown timer

Query Chinese statutory holidays and adjusted working days

Lunar and solar calendar with solar terms and festivals

Equal principal and interest mortgage calculator

Personal income tax and new property tax calculator

Commercial, provident fund and combined mortgage calculator

Compound and simple interest calculation

Percentage, discount and profit margin calculator

Body fat percentage estimator

Food calories and daily calorie needs

International shoe size comparison

Pace, speed and finish time calculator

Calculate best bedtime and wake-up time

Online keyboard key tester

Car loan monthly payment calculator

Calculate interest saved by early repayment

Statutory retirement age calculator with delayed retirement

SIP and lump sum investment return calculator

Safe period, ovulation and period prediction

Screen dead pixel, color and brightness test

Mouse button and scroll wheel tester

International clothing size comparison

Chinese zodiac sign query and personality analysis

Western zodiac sign query and horoscope

Ratio conversion and solving

Infant height and weight development standards

Calculate ideal weight range from height

Daily recommended water intake calculator

China postal code lookup

China telephone area code lookup

License plate region lookup

Mobile number location and carrier lookup

IP geolocation lookup

Traditional, brand and flag color lookup

Daily Five Elements clothing color guide

Random lottery number generator

Play specific frequency sound to clean phone speaker

Weather forecast query

Express logistics tracking

Historical exchange rate trend chart

Ring size measurement and conversion

Pupillary distance and prescription conversion

Gold price per gram or ounce conversion

Fuel consumption, cost and range calculator

Parking fee calculation

Residential tiered electricity bill calculator

Compare returns of different wealth management products

Five insurances and one fund calculator

Housing fund loan and withdrawal calculator

Pregnancy due date calculation

Predict child blood type from parents

Visual acuity conversion

Time difference between two cities and adjustment tips

Look up waste classification by item name

Convert cat or dog age to human age

Baking unit conversion for cups, grams, spoons, ml

Estimate renovation cost by area and style

Estimate carbon emissions from travel, electricity and food

Calculate required AC power by room area

Look up international telephone country codes

China and international emergency phone numbers

Calculate required tile quantity and cost by area

Calculate required paint amount by area

Estimate highway toll fees

Express insurance fee calculator

Pet healthy weight range chart

Wedding expense budget allocation

Find auspicious dates for moving

Cooking ingredient substitution

Look up wine vintage ratings by region

Express package size reference

Cute kaomoji ready to copy

Count Chinese characters, words and characters

Online text difference comparison

Remove duplicate lines, keep first occurrence

Sort lines ascending, descending, natural or random

Find and replace with regex support

UPPER, lower, Title, Camel, Snake, Kebab and Constant case

Convert between full-width and half-width characters

Convert between Simplified and Traditional Chinese

Gzip and Base64 text compression and decompression

Split text lines by delimiter

Join multiple lines into one

Add line numbers to each line

Add prefix or suffix to each line

Extract matching content with regex

Filter lines by condition including regex

Randomly shuffle line order

Reverse entire text or line by line

Batch add or remove indentation

Trim spaces and remove extra spaces and blank lines

Convert text to URL-friendly slug

Generate fancy text styles

Convert text to Martian text

Convert text to ASCII art

Display text vertically

Character and word frequency statistics with visualization

Detect sensitive and forbidden words in content

CSV and TSV format conversion

Visually edit and generate Markdown tables

Template variable replacement with Mustache style

Chinese article auto typesetting

Search and copy emojis by keyword

Math, arrows, currency, shapes and other special symbols

Convert Chinese characters to pinyin with tones

Read text aloud via Web Speech API

Generate banner images from text

Generate beautiful quote images from text

Generate social media share images from text

Generate WeChat moments images from text

Generate OG social share preview images from text

Generate electronic business card images from text

Generate holiday and birthday greeting card images

Generate honor certificate images from text

Generate beautiful calendar images from text

Generate mind map from text outline

Generate flowchart from text description

Generate timeline from text events

Generate beautiful table images from text data

Generate palettes in one click and copy the hex values into your design.

Convert HEX, RGB, HSL, CMYK and HSV live with one synced picker.

Make QR codes with your logo and colors, then export vector SVG.

Scan a QR from an image or camera and copy its link or text.

Create Code128, EAN, UPC and more barcodes as vector files.

Read the value of a 1D barcode image for fast stock checks.

Build CSS animations on a timeline and copy the pure CSS out.

Turn code into themed, highlighted images for sharing.

Look up visa and ID photo sizes with a print-layout calculator.

Check A/B/C sizes and convert to pixels at your print DPI.

Browse HTTP status codes by class with causes and fixes.

Copy common Git commands grouped by everyday scenario.

Compare CN, US, EU and JP clothing and shoe sizes.

Check plug shapes and voltage by country before you travel.

Review CPR, burns and choking steps for common emergencies.

Explore all 118 elements, color-coded by period and group.

Look up regex metacharacters and ready email, phone patterns.

Map symbols to entity names and numbers both ways.

Learn when to use px, rem, em or vh in responsive layouts.

Look up MIME types by extension or type, both directions.

Browse Unicode by category and copy code points easily.

Match common services to their default port numbers.

Copy Linux commands grouped by files, permissions and more.

Browse VS Code shortcuts for editing and debugging.

Check calories and macros for common foods at a glance.

Compare world times and convert between any two zones.

Find phone dialing and ISO codes by country fast.

See typical ranges for BMI, blood pressure and more.

Keep geometry, algebra and calculus formulas in one place.

See Greek letters with pronunciation and common uses.

Trace Chinese dynasties on a timeline with reign lengths.

Match ISO 4217 codes, symbols and countries quickly.

Skim common VAT, corporate and income tax rates.

Copy web-safe and system font stacks for your CSS.

Decode tire width, ratio and rim size, and compare models.

Look up the standard frequency of any note name.

Grab light speed, gravity and Planck values with units.

See ASCII characters as decimal, hex and symbol.

Find postal and division codes by province, city, district.

Match Chinese license classes to permitted vehicles.

Check standard bed, sofa, table and wardrobe sizes.

Review bleed, DPI, CMYK and finishing for print files.

Compare bra and panty sizes with a fit calculator.

Strip extra nodes and metadata to shrink SVG files.

Make multi-size icons and manifests from one image.

Render text into styled images for social covers.

Get a poetic Chinese name for any color value.

Build complementary and triadic schemes from the wheel.

Design multi-layer box-shadow visually and copy CSS.

Adjust rotate, scale and skew with live 2D/3D preview.

Shape easing curves by dragging control points.

Extract a full palette from an image or keywords.

Create linear, radial and conic gradients visually.

Build a 50-950 shade scale from one base color.

Check foreground and background contrast vs WCAG.

Preview your UI under common color-blind modes.

Export palettes to CSS, SCSS, Tailwind or JSON.

Drop layout blocks into quick placeholder wireframes.

Generate SVG or PNG placeholders at any size.

Generate filler text by paragraph, sentence or word.

Turn text into a word cloud by frequency.

Word cloud with vector SVG and hover details.

Craft frosted-glass card CSS with a live preview.

Make soft raised or pressed UI effects in CSS.

Stack text-shadows into a neon glow effect.

Build a Tailwind config visually and export it.

Generate a full Tailwind palette from one brand color.

Combine icons and fonts into a simple logo sketch.

Wrap screenshots in iPhone or Mac device frames.

Make a TOTP QR and verify the rolling code.

Compress PNG, JPG and WebP while keeping images crisp and cutting load time.

Convert JPG, PNG, WebP and AVIF while keeping transparency and color.

Crop by free or fixed ratios at exact pixels, then rotate and scale for covers.

Resize with ratio locked or free, by edge, percentage or pixels for batches.

Rotate by 90 steps or any angle, straighten shots and pick a fill color.

Flip horizontally or vertically for mirror selfies and reversed stamp text.

Apply film, vintage, B&W and pastel presets with live preview and export.

Tune brightness, contrast, exposure and gamma to rescue bad exposures.

Shift hue, saturation, temperature and tint to unify or warm a photo set.

Enhance edges so blurry screenshots, scans and product shots look crisp.

Reduce color and luminance noise in night and high-ISO shots, keeping detail.

Brush mosaic over a region or the whole image, with adjustable block size.

Add rounded corners with per-corner radius and a custom background fill.

Add inner or outer borders with custom color, width and rounding for IDs.

Erase flash red-eye in one click by locating pupils and catchlights.

Add text or logo watermarks with adjustable position, opacity and tiling.

Embed an invisible watermark that survives cropping and screenshots.

Blend images with multiply, screen and other modes for double exposures.

Compare two images side by side or with a drag slider, before and after.

Slice one image into a 3x3 grid exported in order for a seamless feed.

Arrange photos into grid, free or magazine layouts with adjustable gaps.

Join images horizontally or vertically into one long picture for guides.

Pull dominant tones and a palette from a photo and export HEX swatches.

Check dimensions, format, size, DPI and color space to verify specs.

Parse shooting time, camera model, aperture, shutter and GPS from EXIF.

Strip shooting time, device and GPS metadata in one click for privacy.

Turn image sequences or frames into a GIF with rate, size and loop control.

Break a GIF into PNG frames to grab one or export the whole sequence.

Shrink GIF size by reducing colors, dropping frames and scaling.

Crop a GIF's frame area to drop bars or focus the subject, still playable.

Change a GIF's speed for slow-mo or fast-forward without quality loss.

Overlay text that follows GIF frames for meme captions and callouts.

Stamp dozens of images with one watermark at once, saving sellers time.

Compress a whole folder at uniform quality for faster uploads.

Convert a pile of mixed images to one format for compatible libraries.

Resize many images to one dimension for standard e-commerce art.

Crop a batch by the same region and ratio for screenshots and IDs.

Rename files by sequence, timestamp or rules instead of by hand.

Convert iPhone HEIC photos to JPG so older systems open them.

Convert HEIC photos to lossless PNG, keeping transparency for retouch.

Convert iOS HEIC photos to smaller WebP for web and mini-programs.

Rasterize SVG vector art to PNG at a chosen resolution for crisp art.

Encode images as Base64 strings to inline into HTML, CSS or configs.

Decode Base64 strings back into downloadable image files from code.

Generate a multi-size ICO from PNG or JPG for desktop and browser icons.

Upload one image to auto-generate every favicon size and code.

Convert photos to pixel-art style with adjustable block size for avatars.

Render images as ASCII character art for terminals and code comments.

Trace bitmaps into scalable SVG vectors so logos never blur enlarged.

Turn a photo into a cartoon or comic style avatar that keeps features.

Add background blur and depth of field to make the subject pop.

Add RGB shift, scanlines and tears for a cyberpunk glitch-art cover.

Blend two images into a double-exposure for moody composites.

Add and typeset text on images with fonts, color and shadow.

Convert numbers to and from scientific notation

Convert between Arabic and Roman numerals

Scientific calculator with trigonometry, logarithm and factorial

Fraction addition, subtraction, multiplication and division

Percentage, discount and increase or decrease calculator

Solve proportion A:B = C:D

Calculate permutation and combination numbers

Large number factorial exact calculation

Greatest common divisor and least common multiple calculator

Prime number test and prime list generator

Generate Fibonacci sequence

Mean, median, mode, standard deviation and variance

Plot mathematical functions online

Aspect ratio conversion and calculation

Screen pixel density calculator

Solve 24 game with 4 numbers

Convert between base 2 to 36

Calculate area of circle, rectangle and triangle

Calculate volume of sphere, cylinder and cone

Simple, compound and equal principal and interest calculation

Solve linear, two-variable and quadratic equations

Matrix operations including add, subtract, multiply and determinant

Sudoku auto solver with hints

Convert between degrees, radians and gradients

Convert between Cartesian and polar coordinates

Query Pi to specified number of digits

Common, natural and arbitrary base logarithm

Trigonometric function value calculation and inverse

Addition, subtraction, multiplication and division in different bases

Date interval, projection and working day calculation

Time addition, subtraction, time difference and working hours

Large number comparison and visualization

Probability calculation and distribution query

Arithmetic and geometric series sum

Convert floating-point between decimal and binary

Exact calculation for very large numbers

Convert length, weight, temperature and area

Online geometry drawing and annotation

T-test, chi-square test and basic statistical tests

Definite integral numerical calculation

Generate pie chart from data with custom colors and labels

Generate bar chart with grouping and direction switching

Generate line chart with multiple series and area fill

Visualize CSV, TSV and Markdown table data as chart

Multi-dimensional radar chart for skill assessment

Two-variable scatter plot with trend line fitting

Donut chart with summary data in center

Conversion funnel chart for process analysis

Project progress Gantt chart with task time and progress

Mean, median, mode, standard deviation and quartiles

Area-filled line chart for trend and magnitude changes

Waterfall chart for financial data analysis

Nightingale rose chart for cyclic and directional data

Sankey flow diagram for data flow relationships

Matrix data heatmap with color intensity

Rectangular treemap with area-based proportions

Paste CSV data to generate chart automatically

Paste JSON array data to generate chart automatically

Convert between CSV, JSON, TSV and Markdown table

Frequency histogram and normal distribution fitting curve

Pearson and Spearman correlation coefficient

Chart color palettes with colorblind-friendly options

GitHub-style calendar heatmap for daily data

Ratio, percentage and growth rate calculator

Goal progress and completion rate visualization

Multi-group data comparison visualization

Multi-metric KPI dashboard with cards and charts

Data distribution boxplot with quartiles and outliers

Stock candlestick chart with OHLC prices

Node relationship network graph for topology analysis

Hierarchical sunburst chart for proportions and hierarchy

Icon-based pictorial bar chart

Combined bar and line chart for business reports

Single-value gauge for KPI and completion rate

Multi-dimensional parallel coordinates for multivariate analysis

Time series theme evolution chart for multi-theme changes

Polar coordinates bar chart for cyclic directional data

Sorting algorithm animation with bubble, selection and quick sort

Sample mean confidence interval calculator

One-sample t-test, independent t-test and chi-square test

Merge multiple PDFs into one, reorder pages by drag-and-drop. Runs locally in your browser.

Split a PDF into files by page range, with single-page extraction. Runs in your browser.

Export each PDF page as PNG or JPG, choosing DPI and range. Local in your browser.

Turn JPG/PNG images into a single PDF with adjustable order, margins and size. Processed locally.

Add text or image watermarks to a PDF with custom opacity, angle and position. Runs in your browser.

Rotate selected PDF pages 90, 180 or 270 degrees, one page or many. Done locally in your browser.

Remove blank or extra PDF pages by page number, including batch range delete. All edits stay local.

Extract a page range into a new PDF, leaving the original untouched. Runs in your browser.

Auto-add page numbers to a PDF with custom position, start page and format. Local in your browser.

Drag thumbnails to reorder PDF pages, with reverse and custom sorting. Sorting stays on your device.

Draw or upload a signature onto any PDF page with size and opacity control. Signing is local.

Insert pages from another PDF or blanks at any spot, with batch add. Runs locally in your browser.

Add header and footer text to every PDF page, with page-number variables. Done in your browser.

Export all embedded images from a PDF as separate files. Extraction runs locally in your browser.

Resize PDF pages to A4/A3/Letter or custom, scaling content. Adjustments stay local.

Create printable primary math worksheets by grade, operation and problem count.

Generate Tianzi, Mi and staff paper: set rows, size, color; export HD PDF.

A Pomodoro focus timer with custom work/break lengths, tasks and daily stats.

Plan reviews by the forgetting curve: set a start date for days 1, 2, 4, 7, 15.

Import a name list to pick, group or shuffle people, with a wheel display.

Pick a certificate template, add recipient, award and message; export HD PDF.

Plan each day of a school break; build a timetable with icons and notes.

Build a class timetable with color-coded subjects and notes; export A4 or image.

Enter options and draw one at random with weights and exportable history — settle lunch, chores or raffles.

Set range, count and no-repeat, sort and export — for giveaways, class calls and lottery picks.

Build a weighted wheel, spin to pick a winner and export — great for raffles, class calls and lunch roulette.

Track birthdays, exams and holidays with exact day counts, pin top events, never miss a gift or prep deadline.

Turn text into wave, rainbow and blink animations with live preview and one-click copy for social captions.

Draw on a grid with custom size and palette, undo/redo, export PNG — make game sprites and avatars.

Upload an image, add top and bottom captions, tweak font and stroke, then export a crisp meme for chats.

Hand-draw a signature with mouse or touch, tune stroke and color, export a transparent PNG for contracts.

Generate meaningful baby names by surname and gender, with poetry references and a popularity check.

Click the instant the screen changes color to measure reflexes in ms, with averages and best-score tracking.

Timed typing test reports WPM, accuracy and errors, saves your high score, helps clerical and daily practice.

Answer timed trivia across history, science and entertainment, earn points, pick difficulty, review wrongs.

Pick gradient, geometric or particle mode, set colors and resolution, export HD wallpapers.

Roll D4 to D100 polyhedral dice, throw several at once, see running sum and history for TRPG and board games.

Flip a virtual coin with realistic animation for instant heads or tails, tallying results for tie-breaks.

Recreate the Matrix green code rain full screen, tweak speed, density and color, use as a screensaver.

Full-screen Windows and macOS update screens with a boss-key switch — prank friends or sneak a break.

Turn text into a self-typing animation with adjustable speed, cursor and sound — for video intros and decks.

Generate balanced upper and lower couplets plus a scroll for festivals and weddings, with tonal checks.

Draw I-Ching hexagrams, matchmaker or wealth-deity lots with verse interpretations — a mindful break.

Swipe to merge matching tiles and reach 2048, with undo and high-score tracking — classic puzzle, no download.

Classic Windows minesweeper with reveal, flag and three difficulty levels — a nostalgic brain teaser.

Steer the snake to eat and grow, avoid walls and yourself, with speed control, pause and a high-score log.

Rotate and drop seven tetrominoes, clear lines to score and speed up, with preview and hold — train thinking.

Flip two cards at a time to match pairs in fewer moves, with themes and tiers that train memory.

Watch a color sequence flash, then repeat it; each level adds a step to push your memory span.

Digits flash then vanish; type them back as the count grows — the classic digit-span memory test.

Hear a beat pattern and tap it back in order; difficulty climbs, testing rhythm and reflexes.

Find the single tile whose hue subtly differs; differences shrink each level — a color acuity check.

Choose branches to drive the plot across mystery, fantasy and romance with multiple endings.

Name the ink color of a clashing word — the classic Stroop effect on response inhibition.

Click numbers 1 to 25 in order inside a shuffled grid fast — the focus drill used by pilots.

Spin the wheel over a cuisine library to decide today's meal, add picks and exclude allergies.

Tap to ring a wooden fish with crisp sound, rack up merit with labels, switch sounds or auto-tap.

Play 3x3 tic-tac-toe vs a Minimax AI with three difficulty tiers — easy, yet strategic.