# Kordu Tools > Every tool, one site, your device. Kordu Tools (kordu.tools) offers 238+ free browser-based utilities for image conversion, PDF processing, developer tools, gaming performance, and more. Files are processed locally — nothing leaves your device. No signup, no limits, no nonsense. Built by KORDU LTD, London, UK. ## What Users Can Do - Convert images between 15+ formats (PNG, JPG, WebP, AVIF, HEIC, GIF, BMP, TIFF, SVG, ICO) in the browser - Remove image backgrounds with AI, apply filters, blur/censor areas, add watermarks, pick colours from images - Compress, resize, crop, rotate, and flip images with social media presets - Strip EXIF metadata and GPS data from photos for privacy - Merge, split, compress, and convert PDF files (DOCX, PPTX, JPG to/from PDF) - Format, beautify, minify, and validate JSON, SQL, CSS, JavaScript, YAML, Markdown, and SVG - Generate and decode Base64, JWT tokens, UUIDs, hashes, regex patterns, and cron expressions - Compare text and code with split/unified diff views - Generate secure passwords and passphrases with crack time estimates - Check if passwords appear in known data breaches (Have I Been Pwned k-anonymity) - Look up DNS, MX, SPF, SSL, WHOIS, and subnet records for any domain - Check public IP, ISP, and detect WebRTC leaks - Calculate mortgages, loans, BMI, percentages, compound interest, tips, and 20+ math operations - Convert timezones, calculate date differences, track exact age, and run countdown timers - Generate QR codes, barcodes, UUIDs, fake data, and lorem ipsum text - Check WCAG colour contrast ratios for accessibility compliance - Gaming tools: aim training, reaction tests, sensitivity conversion, D&D tools, Steam ID lookup, and more ## Image Tools - [AI Image Caption & Alt Text Generator](https://kordu.tools/tools/image/image-captioner/): Generate descriptive captions and accessibility alt text for images using AI — free, no account, runs in your browser. - [AI Image Upscaler](https://kordu.tools/tools/image/image-upscaler/): Upscale images 2x or 4x with AI — sharper than bicubic, runs in your browser, no upload needed. - [Animated GIF Creator](https://kordu.tools/tools/image/gif-creator/): Create animated GIFs from multiple images — set frame timing, loop count, and reorder frames. No upload needed. - [Aspect Ratio Calculator](https://kordu.tools/tools/image/aspect-ratio-calculator/): Find the aspect ratio of any image, or resize dimensions while keeping the ratio locked. - [AVIF to JPG Converter](https://kordu.tools/tools/image/avif-to-jpg/): Convert AVIF images to universally compatible JPG in seconds. Adjustable quality, batch support, 100% browser-based — your files never leave your device. - [AVIF to PNG Converter](https://kordu.tools/tools/image/avif-to-png/): Convert AVIF images to lossless PNG with full transparency support. Batch-ready, browser-based — your files never leave your device. - [Background Remover](https://kordu.tools/tools/image/background-remover/): Remove image backgrounds instantly using AI — transparent PNG output, no account needed, runs entirely in your browser. - [BMP to JPG Converter](https://kordu.tools/tools/image/bmp-to-jpg/): Convert oversized BMP bitmap files to compact JPG. Up to 98% smaller file size, adjustable quality, batch support — no upload required. - [BMP to PNG Converter](https://kordu.tools/tools/image/bmp-to-png/): Convert uncompressed BMP files to web-ready PNG with zero quality loss. Batch support, instant results — no upload required. - [Depth Map Generator](https://kordu.tools/tools/image/depth-map-generator/): Generate depth maps from any photo using AI. Visualize 3D structure with colorized depth estimation — runs in your browser. - [EXIF Remover](https://kordu.tools/tools/image/exif-remover/): Strip EXIF, GPS, and all metadata from photos before sharing — protects your location and privacy. - [Face Blur Tool](https://kordu.tools/tools/image/face-blur/): Auto-detect and blur faces in photos with AI. GDPR-friendly privacy protection — runs entirely in your browser. - [Favicon Generator](https://kordu.tools/tools/image/favicon-generator/): Generate a complete favicon set from any image — ICO, PNG at 16×16 through 512×512, and Apple Touch Icon. Download as ZIP. - [GIF to JPG Converter](https://kordu.tools/tools/image/gif-to-jpg/): Convert GIF images to JPG with adjustable quality. Extracts the first frame from animated GIFs. Batch support — no upload required. - [GIF to PNG Converter](https://kordu.tools/tools/image/gif-to-png/): Convert GIF to lossless PNG with full alpha transparency. First frame extracted from animated GIFs. Batch support — no upload required. - [HEIC to JPG Converter](https://kordu.tools/tools/image/heic-to-jpg/): Convert iPhone HEIC photos to JPG instantly. Open Apple photos on any Windows PC, Android, or app — no software, no upload required. - [HEIC to PNG Converter](https://kordu.tools/tools/image/heic-to-png/): Convert iPhone HEIC photos to lossless PNG. Full transparency support, no quality loss — no upload required. - [ICO to PNG Converter](https://kordu.tools/tools/image/ico-to-png/): Extract the largest image from an ICO favicon file and save as high-quality PNG. Batch support — no upload required. - [Image Blur & Censor](https://kordu.tools/tools/image/image-blur-censor/): Blur, pixelate, or black out any region of an image. Redact sensitive info, faces, text, and licence plates. - [Image Color Picker](https://kordu.tools/tools/image/image-color-picker/): Pick colors from any image and get HEX, RGB, and HSL values. Extract a full color palette instantly. - [Image Compressor](https://kordu.tools/tools/image/image-compressor/): Compress PNG, JPG, WebP, AVIF, GIF, BMP, ICO and more — reduce file size without losing visual clarity. - [Image Cropper](https://kordu.tools/tools/image/image-cropper/): Crop images visually with aspect ratio presets and social media sizes — Instagram, YouTube, Twitter, and more. - [Image Filters](https://kordu.tools/tools/image/image-filters/): Apply photo filters and adjustments — brightness, contrast, saturation, grayscale, sepia, vintage, and more. - [Image Resizer](https://kordu.tools/tools/image/image-resizer/): Resize images to exact pixel dimensions or percentage — aspect ratio lock, social media presets, no upload needed. - [Image Rotate & Flip](https://kordu.tools/tools/image/image-rotate-flip/): Rotate images 90°, 180°, or flip horizontally and vertically — instant, batch supported, no upload needed. - [Image to Base64 Encoder](https://kordu.tools/tools/image/image-to-base64/): Convert any image to Base64 — get data URL, raw Base64, CSS background-image rule, or HTML img snippet. - [Image to Text (OCR)](https://kordu.tools/tools/image/image-ocr/): Extract text from images free online. AI-powered OCR supports 12 languages — copy or download extracted text instantly. - [Image Watermark](https://kordu.tools/tools/image/image-watermark/): Add text watermarks to photos — custom position, opacity, font size, rotation, and tiling. Free, no upload. - [JPG to AVIF Converter](https://kordu.tools/tools/image/jpg-to-avif/): Convert JPG to AVIF for next-gen web compression — up to 50% smaller files at the same visual quality. Batch support, browser-based, no upload. - [JPG to PNG Converter](https://kordu.tools/tools/image/jpg-to-png/): Convert JPG to lossless PNG instantly. No additional quality loss, full transparency canvas — batch support, no upload required. - [JPG to WebP Converter](https://kordu.tools/tools/image/jpg-to-webp/): Convert JPG to WebP for 25–34% smaller files at the same quality. Ideal for web performance. Batch support — no upload required. - [Object Detection](https://kordu.tools/tools/image/object-detector/): Detect and identify 80+ objects in images with AI — labeled bounding boxes and confidence scores, runs in browser. - [PNG to AVIF Converter](https://kordu.tools/tools/image/png-to-avif/): Convert PNG to AVIF for next-gen web compression — up to 50% smaller than PNG. Batch support, browser-based, no upload. - [PNG to ICO Converter](https://kordu.tools/tools/image/png-to-ico/): Create multi-size ICO favicon files from any PNG. Select 16×16 through 256×256 sizes, bundled into one .ico file — no upload required. - [PNG to JPG Converter](https://kordu.tools/tools/image/png-to-jpg/): Convert PNG to JPG with adjustable quality. Reduce file sizes dramatically for sharing and web use. Batch support — no upload required. - [PNG to SVG Converter — VTracer & Fast Trace](https://kordu.tools/tools/image/png-to-svg/): Vectorize images to SVG with two engines — a fast bitmap tracer for logos/icons and a VTracer WASM engine for high-quality photo and color artwork tracing. - [PNG to WebP Converter](https://kordu.tools/tools/image/png-to-webp/): Convert PNG to WebP for 25–34% smaller files with full transparency. Faster pages, no quality loss. Batch support — no upload required. - [SVG to JPG Converter](https://kordu.tools/tools/image/svg-to-jpg/): Convert SVG vector graphics to JPG at any resolution. Set custom dimensions, adjust quality — ideal for print and social media. No upload required. - [SVG to PNG Converter](https://kordu.tools/tools/image/svg-to-png/): Convert SVG vector graphics to PNG at any resolution with transparency preserved. Set custom dimensions — no upload required. - [TIFF to JPG Converter](https://kordu.tools/tools/image/tiff-to-jpg/): Convert large TIFF scanner files to compact JPG — up to 95% smaller. Adjustable quality, batch support — no upload required. - [TIFF to PNG Converter](https://kordu.tools/tools/image/tiff-to-png/): Convert TIFF scanner files to web-compatible PNG with zero quality loss. Batch support — no upload required. - [WebP Converter](https://kordu.tools/tools/image/webp-converter/): Convert WebP to PNG or JPG instantly. Choose lossless PNG or compressed JPG with adjustable quality. Batch support — no upload required. ## PDF Tools - [Compress PDF](https://kordu.tools/tools/pdf/compress-pdf/): Reduce PDF file size without losing quality — compress images and strip metadata entirely in your browser. - [JPG to PDF](https://kordu.tools/tools/pdf/jpg-to-pdf/): Convert JPG, PNG, and WebP images to a multi-page PDF — set page size, margins, and order in your browser. - [Merge PDF](https://kordu.tools/tools/pdf/merge-pdf/): Combine multiple PDF files into one document — drag, reorder, and merge with no upload and no watermark. - [PDF Organizer](https://kordu.tools/tools/pdf/organize-pdf/): Reorder, rotate, delete, and extract PDF pages using visual thumbnails — all in your browser. - [PDF to JPG](https://kordu.tools/tools/pdf/pdf-to-jpg/): Convert every page of a PDF to a JPG image — choose quality and resolution, then download all pages as a ZIP. - [PDF to PNG](https://kordu.tools/tools/pdf/pdf-to-png/): Convert every page of a PDF to a lossless PNG image — choose resolution, select pages, and download all as a ZIP. - [PDF to PowerPoint](https://kordu.tools/tools/pdf/pdf-to-pptx/): Convert PDF pages to PowerPoint slides — each page becomes a high-quality slide in your browser. - [PDF to Word](https://kordu.tools/tools/pdf/pdf-to-docx/): Convert PDF to editable Word DOCX — extracts text and heading hierarchy entirely in your browser. - [PowerPoint to PDF](https://kordu.tools/tools/pdf/pptx-to-pdf/): Convert PowerPoint PPTX and legacy PPT presentations to PDF — modern files stay local, legacy files use secure server conversion. - [Split PDF](https://kordu.tools/tools/pdf/split-pdf/): Split a PDF into individual pages, custom page ranges, or equal-sized chunks — all in your browser. - [Unlock PDF](https://kordu.tools/tools/pdf/unlock-pdf/): Remove PDF password restrictions — unlock copy, print, and edit permissions instantly in your browser. - [Word to PDF](https://kordu.tools/tools/pdf/docx-to-pdf/): Convert Word DOCX and legacy DOC files to PDF — modern files stay local, legacy files use secure server conversion. ## Text Tools - [Add Line Numbers](https://kordu.tools/tools/text/add-line-numbers/): Add line numbers to text with customisable separator, start number, and zero-padding. - [AI Language Detector](https://kordu.tools/tools/text/language-detector-ai/): Identify the language of any text with a BERT neural network — accurate on short snippets and closely related languages. Runs on-device. - [AI Sentiment Analyzer](https://kordu.tools/tools/text/sentiment-analyzer-ai/): Analyze text sentiment with AI. DistilBERT understands context, negation, and sarcasm — runs on-device with no data uploaded. - [AI Text Summarizer](https://kordu.tools/tools/text/text-summarizer/): Summarize articles, essays, and documents with AI. Choose length, get bullet points, see word-count reduction. Runs on-device. - [BBCode Generator](https://kordu.tools/tools/text/bbcode-generator/): Write BBCode with a visual toolbar and live preview — bold, links, images, quotes, spoilers, and more without memorising tags. - [Case Converter](https://kordu.tools/tools/text/case-converter/): Convert text between UPPERCASE, lowercase, Title Case, camelCase, snake_case, kebab-case, and more — instantly. - [Fancy Text Generator](https://kordu.tools/tools/text/fancy-text-generator/): Convert plain text into bold, italic, script, fraktur, small caps, upside down, and 20+ Unicode styles. - [Find and Replace](https://kordu.tools/tools/text/find-and-replace/): Find and replace text online with regex support, case sensitivity, and replace-all options. - [Language Detector](https://kordu.tools/tools/text/language-detector/): Detect the language of any text instantly — identifies 187 languages with confidence scores. No AI model required. - [Lorem Ipsum Generator](https://kordu.tools/tools/text/lorem-ipsum-generator/): Generate Lorem Ipsum placeholder text as paragraphs, sentences, words, or bytes. Start with the classic opening or use randomised text. - [Readability Score](https://kordu.tools/tools/text/readability-score/): Check text readability using the Flesch Reading Ease score and Flesch-Kincaid grade level. - [Remove Duplicate Lines](https://kordu.tools/tools/text/remove-duplicate-lines/): Remove duplicate lines from text instantly. Keeps first occurrence, case-sensitive or insensitive. - [Remove Empty Lines](https://kordu.tools/tools/text/remove-empty-lines/): Remove blank lines from text, or collapse multiple blank lines into one. Free online tool. - [Sentiment Analyzer](https://kordu.tools/tools/text/sentiment-analyzer/): Analyze text sentiment instantly — see positive, negative, and neutral scores with a per-word breakdown. No AI model required. - [Slug Generator](https://kordu.tools/tools/text/slug-generator/): Convert any title or phrase into a clean URL slug with hyphen, underscore, or dot separator. - [Sort Lines](https://kordu.tools/tools/text/sort-lines/): Sort lines alphabetically, by length, numerically, or randomly. Optionally remove duplicates. - [Text Cleaner](https://kordu.tools/tools/text/text-cleaner/): Clean up messy text — strip HTML, remove extra whitespace, trim blank lines, normalize line endings, and more. - [Text Reverser](https://kordu.tools/tools/text/text-reverser/): Reverse text by characters, words, or lines instantly. Free online text reverser. - [Text Similarity Checker](https://kordu.tools/tools/text/text-similarity/): Compare two texts with AI semantic similarity — detects duplicate content and plagiarism with a 0–100% match score. - [Word Counter](https://kordu.tools/tools/text/word-counter/): Count words, characters, sentences, and paragraphs with reading time, speaking time, and keyword density. ## Developer Tools - [.gitignore Generator](https://kordu.tools/tools/developer/gitignore-generator/): Generate .gitignore files for Node.js, Python, Go, Rust, React, Next.js, Vite, Laravel, Django, Docker, Terraform, VS Code, macOS and more. - [AI Token Counter](https://kordu.tools/tools/developer/token-counter/): Count tokens for GPT-4o, Claude, Gemini, and more. Exact tiktoken counts for OpenAI models, estimates for others, with API cost breakdown. - [Base64 Encoder/Decoder](https://kordu.tools/tools/developer/base64-encoder/): Encode text or files to Base64 or decode Base64 strings back to plain text — real-time, fully in your browser. - [chmod Calculator](https://kordu.tools/tools/developer/chmod-calculator/): Calculate Linux and Unix file permissions. Toggle read, write, and execute for owner, group, and others — get octal, symbolic, and chmod command. - [Cron Expression Explainer](https://kordu.tools/tools/developer/cron-explainer/): Paste any cron expression and get a plain English explanation, per-field breakdown, and a preview of the next scheduled run times. - [Cron Expression Generator](https://kordu.tools/tools/developer/cron-generator/): Build cron expressions visually or decode any cron string into plain English with next run previews. - [CSS Gradient Generator](https://kordu.tools/tools/developer/css-gradient-generator/): Build linear, radial, and conic CSS gradients visually with a live preview and color stop editor. - [CSS Minifier](https://kordu.tools/tools/developer/css-minifier/): Minify and compress CSS for production — strip whitespace, merge rules, and show size reduction instantly. - [CSV to JSON Converter](https://kordu.tools/tools/developer/csv-json-converter/): Convert CSV to JSON or JSON to CSV instantly — paste data or upload a file with full delimiter and header control. - [Curl to JavaScript Fetch Converter](https://kordu.tools/tools/developer/curl-to-fetch/): Convert curl commands to JavaScript fetch API code instantly. Supports all common flags: headers, POST data, auth, form data, and more. - [Diff Checker](https://kordu.tools/tools/developer/diff-checker/): Compare two texts, code files, or documents side by side — word-level diff highlighting, private and browser-based. - [Hash Generator](https://kordu.tools/tools/developer/hash-generator/): Generate MD5, SHA-1, SHA-256, and SHA-512 hashes from text or files instantly in your browser. - [HTML Encoder / Decoder](https://kordu.tools/tools/developer/html-encoder-decoder/): Encode the five HTML-special characters into entities and decode named, decimal, and hex entities back to text. Runs fully in-browser. - [HTML Formatter](https://kordu.tools/tools/developer/html-formatter/): Format and beautify messy HTML with configurable indent, wrapping, and attribute handling — paste or type, get clean output instantly. - [HTML to Markdown](https://kordu.tools/tools/developer/html-to-markdown/): Convert HTML to clean Markdown — paste HTML source and get properly formatted .md output with headings, links, lists, and code blocks. - [HTTP Status Code Reference](https://kordu.tools/tools/developer/http-status-codes/): Complete HTTP status code reference with descriptions, causes, and examples — searchable and filterable by category. - [JavaScript Beautifier](https://kordu.tools/tools/developer/javascript-beautifier/): Format and beautify minified or messy JavaScript code instantly. 2 or 4 space indent, or tabs. - [JavaScript Minifier](https://kordu.tools/tools/developer/js-minifier/): Minify JavaScript code with Terser — mangle variables, strip dead code, and show size reduction instantly. - [JSON Formatter](https://kordu.tools/tools/developer/json-formatter/): Format, validate, and minify JSON instantly — with configurable indentation, error location, and tree view. - [JSON to TypeScript](https://kordu.tools/tools/developer/json-to-typescript/): Paste JSON and generate TypeScript interfaces or type aliases instantly. Handles nested objects, arrays, and nullables. Free, in-browser. - [JWT Decoder](https://kordu.tools/tools/developer/jwt-decoder/): Decode and inspect JWT tokens — view header, payload, claims, and expiry status without sending data to any server. - [JWT Encoder](https://kordu.tools/tools/developer/jwt-encoder/): Build and sign JWT tokens with a visual editor — set header, payload claims, expiry, and sign with HS256/HS384/HS512. - [Markdown Preview](https://kordu.tools/tools/developer/markdown-preview/): Write Markdown and see a live GitHub-flavoured HTML preview side by side — export clean HTML instantly. - [Regex Tester](https://kordu.tools/tools/developer/regex-tester/): Test regular expressions live with color-coded match highlighting, capture groups, replace mode, and common presets. - [SQL / CSV / JSON Converter](https://kordu.tools/tools/developer/data-converter/): Convert between SQL INSERT statements, CSV, and JSON. Transform CSV to SQL INSERTs, SQL to JSON, or JSON to SQL INSERTs with dialect options. - [SQL Formatter](https://kordu.tools/tools/developer/sql-formatter/): Format, beautify, and minify SQL queries with dialect support for MySQL, PostgreSQL, SQL Server, BigQuery, and more. - [SSL Certificate Decoder](https://kordu.tools/tools/developer/ssl-certificate-decoder/): Paste any PEM-encoded SSL/TLS certificate and instantly decode all X.509 fields: subject, issuer, validity, SANs, key usage, fingerprints, and more. - [String Escape / Unescape](https://kordu.tools/tools/developer/string-escape/): Escape or unescape strings for JSON, HTML, JavaScript, CSV, and SQL — real-time, client-side, zero dependencies. - [SVG Optimizer](https://kordu.tools/tools/developer/svg-optimizer/): Optimize and compress SVG files with SVGO — remove metadata, comments, and redundant paths for 40–80% size reduction. - [Timestamp Converter](https://kordu.tools/tools/developer/timestamp-converter/): Convert Unix timestamps to human-readable dates or dates to epoch timestamps — with timezone support and multiple formats. - [URL Encoder/Decoder](https://kordu.tools/tools/developer/url-encoder/): Encode or decode URLs and query string components instantly — supports encodeURIComponent, decodeURIComponent, and full URL encoding. - [User Agent Parser](https://kordu.tools/tools/developer/user-agent-parser/): Parse any user agent string to detect browser, version, OS, device type, and rendering engine. Includes one-click detection of your own browser. - [UUID Generator](https://kordu.tools/tools/developer/uuid-generator/): Generate cryptographically secure v4 and v7 UUIDs in bulk — copy individually or all at once, instantly in your browser. - [Webhook Tester](https://kordu.tools/tools/developer/webhook-tester/): Get a temporary webhook URL and inspect incoming requests in real time. See headers, body, query params, and get a cURL replay command. - [XML Formatter](https://kordu.tools/tools/developer/xml-formatter/): Format, minify, and validate XML online — syntax checking with clear error messages, configurable indent, real-time output. - [YAML to JSON Converter](https://kordu.tools/tools/developer/yaml-json-converter/): Convert YAML to JSON or JSON to YAML bidirectionally — type preservation, null handling, and configurable indentation. ## Security & Privacy Tools - [Password Breach Checker](https://kordu.tools/tools/security/password-breach-checker/): Check if a password appeared in known data breaches using k-anonymity. Only the first 5 SHA-1 hash characters are sent — your password never leaves your browser. - [Password Generator](https://kordu.tools/tools/security/password-generator/): Generate cryptographically secure passwords with custom length (8–128), character sets, entropy display, and exclude-ambiguous option. Runs in your browser. - [Password Strength Meter](https://kordu.tools/tools/security/password-strength-meter/): Test how strong your password is — entropy, crack time estimate, and a detailed requirements checklist. - [TOTP Code Generator](https://kordu.tools/tools/security/totp-generator/): Generate live TOTP (2FA) codes from any base32 secret key. Supports 6 and 8 digit codes with 30 or 60 second periods. ## Math & Numbers Tools - [Area & Perimeter Calculator](https://kordu.tools/tools/math/area-perimeter-calculator/): Calculate area and perimeter for rectangles, triangles, circles, trapezoids, ellipses, and regular polygons with formula diagrams. - [Circle Calculator](https://kordu.tools/tools/math/circle-calculator/): Calculate radius, diameter, circumference, and area from any single value. Arc length and sector area included with an SVG diagram. - [Exponent & Power Calculator](https://kordu.tools/tools/math/exponent-calculator/): Calculate any base raised to any power, including negative and fractional exponents, with scientific notation and power rules reference. - [Factorial Calculator](https://kordu.tools/tools/math/factorial-calculator/): Calculate n factorial, double factorial, subfactorial, trailing zeros, and digit count. BigInt support for exact large number results. - [Fibonacci Generator](https://kordu.tools/tools/math/fibonacci-generator/): Generate Fibonacci sequences up to any term, check if a number is Fibonacci, and watch golden ratio convergence. BigInt support. - [Fraction Calculator](https://kordu.tools/tools/math/fraction-calculator/): Add, subtract, multiply, or divide fractions with step-by-step solutions. Simplify, convert between decimals and percentages, and work with mixed numbers. - [GCD & LCM Calculator](https://kordu.tools/tools/math/gcd-lcm-calculator/): Find the GCD and LCM of up to 10 numbers at once with step-by-step Euclidean algorithm and prime factorization methods. - [Grade Calculator](https://kordu.tools/tools/math/grade-calculator/): Calculate weighted course grades, convert letter grades to 4.0-scale GPA, and find the minimum score needed on your final exam. - [Logarithm Calculator](https://kordu.tools/tools/math/logarithm-calculator/): Calculate log base 10, natural log (ln), log base 2, or any custom base. Antilog mode and logarithm rules reference included. - [Matrix Calculator](https://kordu.tools/tools/math/matrix-calculator/): Perform matrix addition, subtraction, multiplication, determinant, inverse, transpose, and row echelon form on matrices up to 6×6. - [Number Base Converter](https://kordu.tools/tools/math/number-base-converter/): Convert numbers between binary, octal, decimal, hex, and any base from 2 to 36 with live updates. Signed two's complement and bit-length selector included. - [Number to Words Converter](https://kordu.tools/tools/math/number-to-words/): Convert any number to English words, currency format, ordinals, or check-writing format. Supports numbers up to vigintillions and multiple currencies. - [Percentage Calculator](https://kordu.tools/tools/math/percentage-calculator/): Calculate X% of Y, find what percentage X is of Y, or compute percentage increase and decrease. Results update as you type. - [Permutation & Combination Calculator](https://kordu.tools/tools/math/permutation-combination-calculator/): Calculate nPr permutations and nCr combinations with step-by-step formula breakdowns. Supports with and without repetition. BigInt precision. - [Prime Number Tools](https://kordu.tools/tools/math/prime-number-tools/): Check if a number is prime, find prime factorization, list all primes in a range using the Sieve of Eratosthenes, or find the Nth prime. - [Probability Calculator](https://kordu.tools/tools/math/probability-calculator/): Calculate single event, compound AND/OR, conditional, and Bayes theorem probabilities with formula display. Results as fractions, decimals, and percentages. - [Quadratic Equation Solver](https://kordu.tools/tools/math/quadratic-equation-solver/): Solve ax² + bx + c = 0 with real or complex roots, discriminant, vertex form, axis of symmetry, and a step-by-step parabola graph. - [Random Number Generator](https://kordu.tools/tools/math/random-number-generator/): Generate random numbers, roll polyhedral dice, flip coins, pick random items from a list, or draw lottery numbers. Cryptographic option included. - [Ratio Calculator](https://kordu.tools/tools/math/ratio-calculator/): Simplify ratios, scale to a target value, compare two ratios for equivalence, and convert between ratios, fractions, and percentages. Aspect ratio presets included. - [Roman Numeral Converter](https://kordu.tools/tools/math/roman-numeral-converter/): Convert numbers to Roman numerals and back instantly. Supports 1–3999, batch conversion, year mode, and a subtractive notation reference table. - [Scientific Calculator](https://kordu.tools/tools/math/scientific-calculator/): A full-featured scientific calculator with trigonometry, logarithms, exponents, roots, memory functions, and calculation history. Full keyboard support. - [Square Root Calculator](https://kordu.tools/tools/math/square-root-calculator/): Calculate square roots, cube roots, and any nth root with simplified radical form and decimal precision up to 15 places. - [Statistics Calculator](https://kordu.tools/tools/math/statistics-calculator/): Calculate mean, median, mode, standard deviation, variance, quartiles, skewness, kurtosis, and range from any dataset. Histogram included. - [Triangle Calculator](https://kordu.tools/tools/math/triangle-calculator/): Solve any triangle using SSS, SAS, ASA, AAS, or right-triangle mode. Get sides, angles, area, perimeter, and a live SVG diagram with step-by-step solutions. - [Volume & Surface Area Calculator](https://kordu.tools/tools/math/volume-surface-area-calculator/): Calculate volume and surface area for spheres, cylinders, cones, cubes, rectangular prisms, pyramids, and more. Capacity conversion included. ## Unit Converters Tools - [Unit Converter](https://kordu.tools/tools/converters/unit-converter/): Convert length, weight, temperature, data storage, speed, area, volume, and time units instantly. Metric and imperial. ## Time & Date Tools - [Age Calculator](https://kordu.tools/tools/time-date/age-calculator/): Calculate your exact age in years, months, and days with birthday countdown and zodiac sign. - [Business Days Calculator](https://kordu.tools/tools/time-date/business-days-calculator/): Count business days between two dates or add working days to a date. Excludes weekends. Perfect for net-30 invoicing, SLAs, and project deadlines. - [Countdown Timer](https://kordu.tools/tools/time-date/countdown-timer/): Live countdown to any target date or duration with presets, alerts, pause/resume, reminders, and persistence. - [Date Difference Calculator](https://kordu.tools/tools/time-date/date-difference/): Calculate the exact difference between two dates in years, months, days, and business days. - [Pomodoro Timer](https://kordu.tools/tools/time-date/pomodoro-timer/): Pomodoro technique timer with customisable work and break durations, session tracking, and audio alerts. - [Stopwatch](https://kordu.tools/tools/time-date/stopwatch/): Precise stopwatch with lap times, split tracking, and millisecond accuracy. - [Time Duration Calculator](https://kordu.tools/tools/time-date/time-duration-calculator/): Calculate time duration between two times or add and subtract hours and minutes from a time. Handles overnight shifts and decimal hours. - [Timezone Converter](https://kordu.tools/tools/time-date/timezone-converter/): Convert times between timezones and compare up to four zones side by side. - [Week Number Calculator](https://kordu.tools/tools/time-date/week-number-calculator/): Find the ISO week number for any date. See day of year, quarter, and days remaining. - [World Clock](https://kordu.tools/tools/time-date/world-clock/): Live world clock showing the current time in major cities. Add any IANA timezone, remove what you don't need, updates every second. ## Color Tools - [Color Blindness Simulator](https://kordu.tools/tools/color/color-blindness-simulator/): See how any color appears under different types of color blindness — protanopia, deuteranopia, tritanopia, and achromatopsia. - [Color Contrast Checker](https://kordu.tools/tools/color/contrast-checker/): Check WCAG color contrast ratios between foreground and background colors. See AA and AAA pass/fail badges instantly. - [Color Palette Generator](https://kordu.tools/tools/color/color-palette-generator/): Generate harmonious color palettes using color theory. Complementary, triadic, analogous, and more. - [Color Picker](https://kordu.tools/tools/color/color-picker/): Pick any color and instantly view HEX, RGB, HSL, HSV, CMYK, alpha, and decimal values. Copy any format with one click. - [Tint & Shade Generator](https://kordu.tools/tools/color/tint-shade-generator/): Generate tints (lighter) and shades (darker) from any base color. Exports CSS variables. ## Data & Files Tools - [Barcode Generator](https://kordu.tools/tools/data/barcode-generator/): Generate Code 128, EAN-13, UPC-A, Code 39, and ITF-14 barcodes online. Download as PNG with custom colors and scale. - [Fake Data Generator](https://kordu.tools/tools/data/fake-data-generator/): Generate realistic test data — names, emails, addresses, UUIDs, phones, and more. Export as JSON or CSV instantly. - [QR Code Generator](https://kordu.tools/tools/data/qr-code-generator/): Generate QR codes for URLs, text, email, WiFi, and phone numbers with custom colors and sizes. Download PNG instantly. ## Finance Tools - [Bill Splitter](https://kordu.tools/tools/finance/bill-splitter/): Split a restaurant bill fairly. Equal split with tip, or itemised split where each person only pays for what they ordered. - [Break-Even Calculator](https://kordu.tools/tools/finance/break-even-calculator/): Calculate break-even units and revenue from fixed costs, variable costs, and selling price. - [Compound Interest Calculator](https://kordu.tools/tools/finance/compound-interest-calculator/): Project how your savings grow over time with compound interest, monthly contributions, and different compounding frequencies. - [Loan Calculator](https://kordu.tools/tools/finance/loan-calculator/): Calculate loan repayments, compare rates, and see how extra payments save time and money. - [Mortgage Calculator](https://kordu.tools/tools/finance/mortgage-calculator/): Calculate monthly mortgage repayments, total interest, and view a full amortisation schedule. - [Profit Margin Calculator](https://kordu.tools/tools/finance/profit-margin-calculator/): Calculate profit margin, markup, and profit amount from cost and selling price. - [ROI Calculator](https://kordu.tools/tools/finance/roi-calculator/): Calculate return on investment (ROI) and annualised CAGR from initial and final value. - [Salary to Hourly Calculator](https://kordu.tools/tools/finance/salary-to-hourly-calculator/): Convert annual salary to hourly rate or hourly rate to salary with a full pay breakdown. - [Sales Tax Calculator](https://kordu.tools/tools/finance/sales-tax-calculator/): Add or remove sales tax/VAT from any price instantly. Quick presets for common rates. - [Tip Calculator](https://kordu.tools/tools/finance/tip-calculator/): Calculate tips instantly with preset percentages, custom amounts, bill splitting, and rounding options. ## SEO & Web Tools - [Meta Tag Previewer](https://kordu.tools/tools/seo/meta-tag-previewer/): Preview how your page looks in Google, Facebook, Twitter, and LinkedIn before you publish. Generate ready-to-paste meta tags. - [Robots.txt Generator](https://kordu.tools/tools/seo/robots-txt-generator/): Generate and validate your robots.txt file with a form builder, CMS presets, and instant error checking. - [Schema Markup Generator](https://kordu.tools/tools/seo/schema-markup-generator/): Generate and validate JSON-LD structured data for 10 schema.org types. Unlock rich results in Google search — free, browser-based. - [UTM Builder](https://kordu.tools/tools/seo/utm-builder/): Build UTM-tagged campaign URLs for Google Analytics 4 in seconds. Quick presets for source, medium, and campaign — no signup. - [XML Sitemap Generator](https://kordu.tools/tools/seo/xml-sitemap-generator/): Generate sitemap.xml from a URL list or validate your existing sitemap — checks priority, changefreq, lastmod, and duplicates. ## Audio & Video Tools - [Speech to Text](https://kordu.tools/tools/audio-video/speech-to-text/): Transcribe audio to text free — upload MP3/WAV/WebM or record from microphone. AI-powered by Whisper, fully on-device and private. ## Fun & Random Tools - [Coin Flip](https://kordu.tools/tools/fun/coin-flip/): Flip a virtual coin online. Fair 50/50 heads or tails with animation, flip history, and statistics tracker. - [Dice Roller](https://kordu.tools/tools/fun/dice-roller/): Roll virtual dice online — d4 to d100. Multiple dice, modifiers, D&D presets, and roll history. Free, browser-based. - [Wheel Spinner](https://kordu.tools/tools/fun/wheel-spinner/): Spin a customisable decision wheel online. Add your own items, spin for a random result. Perfect for raffles, random name pickers, and giveaways. ## Encryption & Decryption Tools - [AES Decrypt](https://kordu.tools/tools/encryption/aes-decrypt/): Decrypt AES ciphertext in your browser. Supports GCM, CBC, CTR, and ECB modes with 128/192/256-bit keys. Password never transmitted. - [AES Encrypt](https://kordu.tools/tools/encryption/aes-encrypt/): Encrypt text with AES-256-GCM, AES-CBC, AES-CTR, or AES-ECB in your browser. PBKDF2 key derivation, random IV, zero uploads. - [RSA Decrypt](https://kordu.tools/tools/encryption/rsa-decrypt/): Decrypt RSA-OAEP ciphertext with your PEM private key in the browser. Supports RSA-2048 and RSA-4096. Private key never transmitted. - [RSA Encrypt](https://kordu.tools/tools/encryption/rsa-encrypt/): Encrypt text with RSA-OAEP using a public key in your browser. Generate RSA-2048 or RSA-4096 key pairs. Max ~190 bytes plaintext. Nothing uploaded. ## Gaming Tools - [Aim Trainer](https://kordu.tools/tools/gaming/aim-trainer/): Free browser-based 2D aim trainer with flick, precision, and speed modes. No download or account needed — practice mouse aim and track accuracy, reaction time, and scores. - [CPS Test](https://kordu.tools/tools/gaming/cps-test/): Measure your clicks per second with precision timing. Choose from 1s to 60s modes, view a live per-second chart, and rank from Beginner to Godlike. Supports jitter and butterfly clicking. - [Crosshair Generator](https://kordu.tools/tools/gaming/crosshair-generator/): Design custom crosshairs for CS2, Valorant, and FPS games. Adjust style, size, color, gap, and outline with live preview. Export as PNG or copy CS2 console commands. - [D&D Stat Roller](https://kordu.tools/tools/gaming/dnd-stat-roller/): Roll D&D 5e ability scores with 4d6 drop lowest, 3d6, standard array, or point buy. See individual dice, assign scores to abilities, and copy your stat block. - [Dead Pixel Test](https://kordu.tools/tools/gaming/dead-pixel-test/): Test your monitor for dead or stuck pixels with fullscreen solid color screens. Includes a stuck pixel fixer that rapidly cycles colors to try to revive unresponsive pixels. - [DPS Calculator](https://kordu.tools/tools/gaming/dps-calculator/): Calculate base, effective, burst, and sustained DPS for any weapon. Enter damage, attack speed, crit chance, magazine size, and reload time. Compare two weapons side by side. - [Drop Rate Calculator](https://kordu.tools/tools/gaming/drop-rate-calculator/): Calculate loot drop probabilities, dry streak odds, and how many farming runs you need for 50%, 90%, or 99% confidence. Works for any game or drop rate. - [Encounter Calculator](https://kordu.tools/tools/gaming/encounter-calculator/): Build and balance D&D 5e encounters instantly. Set party size and level, add monsters by CR, and see real-time difficulty ratings with adjusted XP using official DMG rules. - [FOV Calculator](https://kordu.tools/tools/gaming/fov-calculator/): Convert field of view between horizontal, vertical, and diagonal for any aspect ratio. Game presets for CS2, Valorant, Apex, Overwatch 2, and more with a live FOV diagram. - [Gaming Name Generator](https://kordu.tools/tools/gaming/gaming-name-generator/): Generate cool gamertags and gaming usernames instantly. Choose competitive, funny, fantasy, or clean styles. Platform-aware limits for Xbox, PSN, Steam, and Discord. - [GPU Bottleneck Calculator](https://kordu.tools/tools/gaming/bottleneck-calculator/): Find out if your CPU is bottlenecking your GPU. Select your processor, graphics card, resolution, and usage type to get an instant bottleneck percentage with upgrade advice. - [Initiative Tracker](https://kordu.tools/tools/gaming/initiative-tracker/): Track D&D initiative order, HP, AC, and conditions for players and monsters. Auto-sort combatants, manage rounds, apply status effects, and save encounters to resume later. - [Keyboard Tester](https://kordu.tools/tools/gaming/keyboard-tester/): Test every key on your keyboard with a visual layout. Detect ghosting, verify N-key rollover, and identify stuck keys. Works with any keyboard type — mechanical, membrane, USB, or Bluetooth. - [Mechanical Switch Finder](https://kordu.tools/tools/gaming/switch-finder/): Answer 3 questions and get a personalized mechanical keyboard switch recommendation. Compare switches by actuation force, travel, and sound with a filterable chart. - [Monitor Refresh Rate Test](https://kordu.tools/tools/gaming/refresh-rate-test/): Detect your monitor's actual refresh rate by counting real frames in the browser. See your Hz, frame times, and a live motion smoothness test. Supports 60Hz to 360Hz. - [Mouse Polling Rate Test](https://kordu.tools/tools/gaming/polling-rate-test/): Test your mouse polling rate in Hz by moving over a tracking area. See live current, average, min, and max Hz readings with a real-time interval chart and stability score. - [Mouse Sensitivity Converter](https://kordu.tools/tools/gaming/sensitivity-converter/): Convert mouse sensitivity between CS2, Valorant, Apex, Overwatch 2, and 20+ games with accurate cm/360 and eDPI calculations. Instant results, no sign-up. - [Reaction Time Test](https://kordu.tools/tools/gaming/reaction-time-test/): Measure your visual reaction time in milliseconds. Click when the screen turns green across 5 attempts and see your average, rank, and percentile vs the human average of 250ms. - [Steam ID Converter](https://kordu.tools/tools/gaming/steam-id-converter/): Convert between SteamID, SteamID3, SteamID64, and Account ID formats instantly. Paste any Steam ID format and get all others in real time with one click to copy. - [Steam ID Lookup](https://kordu.tools/tools/gaming/steam-id-lookup/): Look up any Steam profile by ID or custom URL. View profile info, all ID formats, VAC bans, game bans, and trade ban status directly from the Steam API. - [Stretched Resolution Calculator](https://kordu.tools/tools/gaming/stretched-resolution-calculator/): Calculate stretched resolution for any monitor. Find the perfect 4:3 or 5:4 stretched res dimensions for CS2 and competitive FPS, with a live viewport comparison. - [Team Randomizer](https://kordu.tools/tools/gaming/team-randomizer/): Randomly split players into balanced teams instantly. Paste names, choose 2–10 teams, and get a fair random split with Fisher-Yates shuffle and round-robin distribution. - [Tournament Bracket Generator](https://kordu.tools/tools/gaming/bracket-generator/): Build single-elimination tournament brackets for 2 to 32 players. Enter names, choose seeding, click to advance winners, and export results. Free, no sign-up. - [Typing Speed Test](https://kordu.tools/tools/gaming/typing-speed-test/): Measure your typing speed in words per minute with timed tests. Choose from English, programming, and gaming text modes with 30-second to 2-minute timers. Track WPM, accuracy, and personal bests. ## Hash Generator & Lookup Tools - [Bcrypt Hash Generator](https://kordu.tools/tools/hashing/bcrypt-generator/): Generate bcrypt hashes with configurable cost factor (4–31). Auto-salted, rainbow-table resistant, fully browser-based. Recommended for secure password storage. - [Bcrypt Hash Verifier](https://kordu.tools/tools/hashing/bcrypt-checker/): Verify a password against a bcrypt hash instantly in your browser. Supports $2a$, $2b$, and $2y$ prefixes. Nothing is uploaded. - [MD5 Decrypt — Hash Lookup](https://kordu.tools/tools/hashing/md5-decrypt/): Reverse-lookup MD5 hashes via rainbow table databases. Not true decryption — MD5 is one-way. Checks multiple sources for the best match rate. - [MD5 Hash Generator](https://kordu.tools/tools/hashing/md5-hash-generator/): Generate MD5 hashes from text in real time. Instant output, uppercase toggle, 100% browser-based. Not for passwords — use bcrypt instead. - [SHA-256 Decrypt — Hash Lookup](https://kordu.tools/tools/hashing/sha256-decrypt/): Look up SHA-256 hashes against rainbow table databases. Not true decryption — SHA-256 is one-way. Works only for common, previously indexed strings. - [SHA-256 Hash Generator](https://kordu.tools/tools/hashing/sha256-hash-generator/): Generate SHA-256 hashes from text instantly. WebCrypto hardware-accelerated, real-time output. Used in Bitcoin, TLS, and digital signatures. Zero uploads. ## Social Media Tools - [Social Media Image Resizer](https://kordu.tools/tools/social/social-image-resizer/): Resize any image to every social media platform size in one click. Download all formats as a ZIP. Free, browser-based. - [TikTok Video Downloader](https://kordu.tools/tools/social/tiktok-video-downloader/): Download TikTok videos without watermark. Paste a TikTok URL and save as MP4 — free, fast, no app needed. ## Encoding & Decoding Tools - [Base64 Decoder](https://kordu.tools/tools/encoding/base64-decode/): Decode Base64 or Base64URL strings to plain text or download as a binary file. Handles MIME line-wrapping and PEM certificates automatically. - [Base64 Encoder](https://kordu.tools/tools/encoding/base64-encode/): Encode text or binary files to Base64 or Base64URL. Supports MIME line wrapping, data URIs, and files up to 50 MB. Fully browser-based. - [Morse Code Decoder](https://kordu.tools/tools/encoding/morse-code-decoder/): Decode Morse code dots and dashes back to plain text. Supports full ITU alphabet including letters, digits, and punctuation. Audio playback available. - [Morse Code Encoder](https://kordu.tools/tools/encoding/morse-code-encoder/): Convert text to International Morse Code with real-time audio playback at 5–20 WPM. Full ITU alphabet, visual beep indicator. Nothing uploaded. ## Network & IP Tools - [DKIM Checker](https://kordu.tools/tools/network/dkim-checker/): Look up and validate DKIM records for any domain — public key, key type, and selector auto-detection. - [DMARC Checker](https://kordu.tools/tools/network/dmarc-checker/): Look up and analyse the DMARC record for any domain — policy, alignment, reporting, and configuration warnings. - [DNS Lookup](https://kordu.tools/tools/network/dns-lookup/): Query all DNS record types for any domain — A, AAAA, MX, TXT, CNAME, NS, SOA, CAA — via Cloudflare DoH. - [Download Time Calculator](https://kordu.tools/tools/network/download-time-calculator/): Calculate how long a file download takes — enter file size and connection speed, get an instant estimate. - [Email Validator](https://kordu.tools/tools/network/email-validator/): Check if an email address is valid — syntax, MX records, and disposable email detection. - [HTTP Headers Viewer](https://kordu.tools/tools/network/http-headers-viewer/): Check what HTTP response headers any URL returns. Inspect security headers, follow redirect chains, and get a security grade. - [IP Geolocation Lookup](https://kordu.tools/tools/network/ip-geolocation/): Look up the location, ISP, and network details for any IP address — city, country, timezone, ASN, and more. - [MAC Address Generator](https://kordu.tools/tools/network/mac-address-generator/): Generate random MAC addresses in bulk — configurable format, case, OUI flags, and unicast/multicast bits. - [MX Lookup](https://kordu.tools/tools/network/mx-lookup/): Look up MX records for any domain — mail server priority, IP addresses, and email provider detection. - [SPF Record Checker](https://kordu.tools/tools/network/spf-checker/): Look up and validate SPF records — parse mechanisms, detect misconfigurations, and check email authentication. - [SSL Certificate Checker](https://kordu.tools/tools/network/ssl-checker/): Check SSL/TLS certificate validity, issuer, expiry, and SANs for any domain via Certificate Transparency logs. - [Subnet Calculator](https://kordu.tools/tools/network/subnet-calculator/): Calculate network address, broadcast, host range, subnet mask, and wildcard from CIDR notation instantly. - [WebRTC Leak Checker](https://kordu.tools/tools/network/webrtc-leak-checker/): Test whether WebRTC exposes your real IP address behind a VPN — detects local and public IP leaks. - [What Is My IP](https://kordu.tools/tools/network/what-is-my-ip/): Find your public IPv4 and IPv6 address with ISP, city, country, ASN, and timezone — loads instantly. - [WHOIS Lookup](https://kordu.tools/tools/network/whois-lookup/): Look up domain registration details — registrar, creation/expiry dates, nameservers, and DNSSEC — via RDAP. ## Calculators Tools - [BMI Calculator](https://kordu.tools/tools/calculators/bmi-calculator/): Calculate your Body Mass Index with metric or imperial units and see your BMI category instantly. - [Recipe Scaler](https://kordu.tools/tools/calculators/recipe-scaler/): Scale any recipe up or down. Paste ingredients, set your target serving count, and get adjusted amounts with smart unit simplification. ## Classical Ciphers Tools - [Caesar Cipher Decoder](https://kordu.tools/tools/ciphers/caesar-cipher-decrypt/): Decode Caesar cipher text with any shift 1–25, or brute-force all 25 shifts instantly. Historically used by Julius Caesar with shift 3. - [Caesar Cipher Encoder](https://kordu.tools/tools/ciphers/caesar-cipher-encrypt/): Encode text with a Caesar cipher shift of 1–25. Classic shift-3 Julius Caesar cipher, real-time output, brute-force mode. Nothing uploaded. - [ROT13 Decoder](https://kordu.tools/tools/ciphers/rot13-decrypt/): Decode ROT13 or ROT47 text instantly. ROT13 is self-inverting — apply it once to encode, once more to decode. Used for spoilers and puzzles on Reddit, Usenet. - [ROT13 Encoder](https://kordu.tools/tools/ciphers/rot13-encrypt/): Encode text with ROT13 or ROT47 instantly. ROT13 is self-inverting — encoding and decoding are the same operation. Used for spoilers and puzzle forums. ## Optional - [All Tools](https://kordu.tools/tools): Browse all 238+ tools by category. - [Blog](https://kordu.tools/blog): Guides and tutorials. - [Privacy Policy](https://kordu.tools/privacy): How we handle data. - [Terms of Service](https://kordu.tools/terms-of-service): Usage terms.