# AltRepo

> AltRepo is a collection of free online tools that skip the sign-up screens. All tools process your files locally in your browser, ensuring complete privacy with no data sent to any server.

This file serves as an LLM-friendly index of all available tools and categories on AltRepo.

## Calculators

Everyday math: mortgages, loans, percentages, interest and more.

- [Age Calculator](https://altrepo.net/calc/age-calculator.html): Free age calculator to find your exact age in years, months, and days from your date of birth, on any past or future date. See the day you were born, your zodiac sign, a birthday countdown, and the difference between two dates. Runs in your browser.
- [Aspect Ratio Calculator](https://altrepo.net/calc/aspect-ratio-calculator.html): Free online aspect ratio calculator. Calculate ratios from width and height, or drag and drop an image to instantly find its exact aspect ratio locally.
- [Auto Loan Calculator](https://altrepo.net/calc/auto-loan-calculator.html): Free auto loan calculator with sales tax and trade-in: find your monthly car payment, total interest, amount financed and a full amortization schedule for 60, 72 or 84 month terms. Works as a car loan and car payment calculator. Runs in your browser.
- [Calorie and TDEE Calculator](https://altrepo.net/calc/calorie-calculator.html): Free calorie and TDEE calculator. Find your BMR, maintenance calories, and daily targets to lose, maintain, or gain weight, plus a balanced macro split. Metric and imperial. Runs in your browser.
- [Chmod Calculator](https://altrepo.net/calc/chmod-calculator.html): Free online chmod calculator. Instantly convert Linux file permissions between octal, symbolic, and visual checkboxes. Copy the exact chmod command you need.
- [Compound Interest Calculator](https://altrepo.net/calc/compound-interest-calculator.html): Free compound interest calculator: see how your savings grow with regular contributions or withdrawals, daily, monthly, yearly or continuous compounding, total interest and a year by year schedule. Runs in your browser.
- [GPA Calculator](https://altrepo.net/calc/gpa-calculator.html): Free GPA calculator to work out your semester and cumulative GPA from your grades and credit hours. Handles weighted and unweighted grades, 4.0 and 5.0 scales, and the GPA you need next term to hit a target. Runs in your browser.
- [Grade Calculator](https://altrepo.net/calc/grade-calculator.html): Free grade calculator to find your weighted course grade, the score you need on a final exam, and a test score from the number of questions wrong. Letter or percentage input, instant results, runs in your browser.
- [IP Subnet Calculator](https://altrepo.net/calc/ip-subnet-calculator.html): Free online IP Subnet Calculator. Instantly calculate network addresses, broadcast addresses, usable host ranges, and CIDR masks.
- [Loan Calculator](https://altrepo.net/calc/loan-calculator.html): Free loan calculator: find your monthly payment, total interest, payoff date and full amortization schedule. Add extra payments and fees to see real APR.
- [Mortgage Calculator](https://altrepo.net/calc/mortgage-calculator.html): Free mortgage calculator: estimate your monthly payment with property taxes, home insurance, PMI and HOA, plus total interest, a full amortization schedule, and a 28/36 affordability check.
- [Multiple Calculators](https://altrepo.net/calc/multiple-calculators.html): Free online multiple calculators. Run two calculators side by side at once, view calculation steps and history, and process everything locally in your browser.
- [Net Worth Calculator](https://altrepo.net/calc/net-worth-calculator.html): Free net worth calculator. Add up your assets and subtract your liabilities to see your net worth, debt-to-asset ratio, liquid versus illiquid breakdown, and a future projection.
- [PayPal Fee Calculator](https://altrepo.net/calc/paypal-fee-calculator.html): Free online PayPal fee calculator. Calculate exactly how much PayPal charges for goods & services, international transfers, and see exactly how much you need to invoice to get paid your full amount.
- [Percentage Calculator](https://altrepo.net/calc/percentage-calculator.html): Free percentage calculator: find what percent of a number, a percentage increase or decrease, percent off a price, and the percent difference between two numbers. Instant results that show the work. Runs in your browser.
- [Profit Margin Calculator](https://altrepo.net/calc/margin-calculator.html): Free online profit margin and markup calculator. Instantly calculate revenue, cost, gross margin, and net profit for e-commerce and dropshipping.
- [PX to REM Converter](https://altrepo.net/calc/px-to-rem-calculator.html): Free online PX to REM and REM to PX calculator. Instantly convert CSS units based on any root font size. Includes dynamic lookup tables and quick presets.
- [Square Footage Calculator](https://altrepo.net/calc/square-footage-calculator.html): Free square footage calculator that adds up multiple rooms and areas at once, including rectangles, triangles, and circles. Switch units and add flooring waste allowances.
- [Standard Deviation Calculator](https://altrepo.net/calc/standard-deviation-calculator.html): Free standard deviation calculator. Paste your numbers to get the sample and population standard deviation, variance, mean, and a clear step-by-step of the math.
- [Time Duration Calculator](https://altrepo.net/calc/time-duration-calculator.html): Free online time duration calculator. Instantly calculate hours and minutes between times, days between dates, and decimal work hours for payroll.
- [Tip Calculator](https://altrepo.net/calc/tip-calculator.html): Free tip calculator to work out how much to tip and split the bill per person. Add tax, tip on the pre-tax or post-tax amount, and round to whole dollars.
- [Unix Timestamp Converter](https://altrepo.net/calc/unix-timestamp-converter.html): Free online Unix Timestamp and Epoch converter. Instantly convert seconds, milliseconds, and dates to UTC, Local Time, ISO 8601, and Discord tags.
- [Water Intake Calculator](https://altrepo.net/calc/water-intake-calculator.html): Free water intake calculator. Find how much water to drink a day based on your weight, exercise, and climate. Results in litres, millilitres, cups, and ounces.

## Color

Pick, check, and extract accessible palettes and contrast.

- [Color Blindness Simulator](https://altrepo.net/color/color-blindness-simulator/): See what color blindness looks like on any image or color palette. Preview all eight color vision deficiency types side by side, free and private in your browser.
- [Color Contrast Checker](https://altrepo.net/color/color-contrast-checker/): Generate accessible color palettes, check WCAG and APCA contrast, preview typography, simulate color-vision conditions, and export CSS, Tailwind, JSON, and W3C design tokens.
- [Color Harmony Generator](https://altrepo.net/color/color-harmony-generator/): Turn one color into complementary, analogous, triadic and tetradic schemes, tints and shades, and a full 50 to 950 UI scale. Export to Tailwind, CSS and JSON. Free.
- [Color Palette Extractor](https://altrepo.net/color/color-palette-extractor/): Extract a color palette from any image in your browser. Dominant colors as HEX, RGB, HSL and OKLCH, named swatches, and CSS, Tailwind or JSON export. Free, private.

## Dev

Formatters, validators, and data converters for developers.

- [Cron Expression Generator](https://altrepo.net/dev/cron-generator.html): Free online cron expression generator and parser. Use the visual builder to create cron schedules, or paste cron syntax to instantly translate it to English.
- [JSON Converter - JSON to CSV, YAML and TypeScript](https://altrepo.net/dev/json-converter/): Free, local JSON converter that runs entirely in your browser. Convert JSON to CSV, YAML, TypeScript interfaces and JSON Lines, and turn CSV or JSONL back into JSON. The data you paste is never uploaded.
- [JSON Formatter & Editor - Free Online JSON Validator & Viewer](https://altrepo.net/dev/json-formatter/): A free, private JSON formatter, editor, and validator that runs in your browser. Online JSON viewer to format, pretty print, repair, query and check JSON files safely.
- [JSON Schema Validator - Free Online JSON Validator](https://altrepo.net/dev/schema-validator/): A fast, free online JSON Schema Validator. Validate your JSON objects against a JSON schema instantly in your browser. Supports Draft 7, Draft 2020-12, and runs securely offline.
- [JWT Decoder](https://altrepo.net/dev/jwt-decoder.html): Free online JWT Decoder. Decode your JSON Web Tokens instantly. 100% local and offline, ensuring your tokens never leave your browser.
- [Robots.txt Generator & Validator](https://altrepo.net/dev/robots-txt-generator.html): Generate and test your robots.txt file instantly. 1-click block AI scrapers like GPTBot, test specific URLs, and download the perfect robots.txt for your site.
- [UI Element Generator](https://altrepo.net/dev/ui-element-generator/): Design glassmorphism, neumorphism and iridescent UI elements in your browser. Tune blur, shadows and a holographic rim, preview live, and copy CSS, Tailwind or SCSS.
- [UUID & GUID Generator](https://altrepo.net/dev/uuid-generator.html): Free online UUID and GUID generator. Instantly create bulk version 4 (random) and version 1 (timestamp) UUIDs. Includes code snippets for Java, JavaScript, Python, and C#.

## Games

A growing collection of fast, offline browser games.

- [Access terminal // AltRepo](https://altrepo.net/games/arg/rabbit-hole.html): Restricted access terminal. Credentials required before the next stage.
- [Cube Runner](https://altrepo.net/games/arcade/cube-runner/): Race to maneuver a cube across collapsing floors while dodging dynamic obstacles in this 3D endless arcade runner.
- [Cyber Raid](https://altrepo.net/games/arcade/cyber-raid/): Play ALT Cyber Raid — a free neon vertical scrolling shooter. Dodge the canyon, blast drones, and battle the Neon Overlord boss in your browser on desktop or mobile. No install.
- [SAFE MAIL](https://altrepo.net/games/arg/safe-mail/): A recovered mailbox puzzle. Read what is left behind, work out the passphrase, and open the desk safe.
- [Tetris](https://altrepo.net/games/arcade/tetris/): Play Tetris free in your browser. Modern SRS controls, hold, ghost piece, T-spins, combos, levels, high scores, touch support, and synthesized sound. Runs fully on your device.
- [Zero Day](https://altrepo.net/games/arg/zero-day/): Zero Day is a terminal-based netrunner game: breach a chain of five security nodes, outrun the trace, and extract the root access token.

## Hash & Crypto

Generate hashes, verify checksums, and hash passwords locally.

- [Bcrypt Hash Generator](https://altrepo.net/hash/bcrypt-password-generator.html): Generate Bcrypt password hashes, choose a work factor, and verify existing hashes locally in your browser.
- [CSP Hash Generator](https://altrepo.net/hash/csp-policy-generator.html): Generate strict Content Security Policy (CSP) headers with SHA-256 hashes for your static HTML files. Processed locally in your browser.
- [File Checksum Verifier](https://altrepo.net/hash/file-checksum-verifier.html): Calculate and verify file checksums locally in your browser. Generate MD5, SHA-1, and SHA-256 hashes for file validation without uploading files.
- [MD5 Hash Generator](https://altrepo.net/hash/md5-hash-generator.html): Generate an MD5 hash or checksum from text locally in your browser. Learn what MD5 is, when to use it, and why MD5 cannot be decrypted.
- [SHA-1 Hash Generator](https://altrepo.net/hash/sha1-hash-generator.html): Generate SHA-1 hashes from text locally in your browser. Learn what SHA-1 is, why SHA-1 is deprecated, and how it compares with SHA-256.
- [SHA-256 Hash Generator](https://altrepo.net/hash/sha256-hash-generator.html): Generate SHA-256 hashes from text locally in your browser. Learn what SHA-256 is, how it works, and why SHA-256 cannot be decrypted.
- [SHA-512 Hash Generator](https://altrepo.net/hash/sha512-hash-generator.html): Generate SHA-512 hashes from text locally in your browser. Learn how SHA-512 works, whether SHA-512 is secure, and how it compares with SHA-256.
- [Text Hash Generator](https://altrepo.net/hash/text-hash-generator.html): Instantly generate MD5, SHA-1, SHA-256, and SHA-512 hashes from any text. Processing is completely local and never leaves your browser.

## Image

Create QR codes and strip or inspect photo metadata offline.

- [EXIF Remover: Remove Photo Metadata Online](https://altrepo.net/image/exif-remover.html): Free EXIF metadata remover. Remove photo metadata online and strip GPS from images in your browser, with no upload required. Works with JPEG, PNG, and WebP.
- [Free QR Code Generator](https://altrepo.net/image/qr-code-generator.html): Create static QR codes instantly. 100% free, no expiration, no watermarks, and offline secure generation. Customize colors, add logos, and download as PNG or SVG.
- [Metadata Viewer](https://altrepo.net/image/exif-viewer.html): Alt Metadata Viewer reads EXIF, XMP, IPTC and ICC metadata from photos, RAW files, videos, PSD and other media. View date taken, camera details, GPS location, color profiles and export metadata as JSON. Files are parsed locally in your browser.

## Social

Safe zones, timestamps, and thumbnails for content creators.

- [Instagram Reels Safe Zone Template](https://altrepo.net/social/instagram-reels-safe-zone.html): Check your Instagram Reel dimensions and size. Download our free 1080x1920 transparent PNG safe zone template for Canva, CapCut, or iOS.
- [TikTok Safe Zone Template & Checker](https://altrepo.net/social/tiktok-safe-zone.html): Free TikTok safe zone checker and template generator. Preview your videos or instantly download a 1080x1920 transparent PNG overlay for CapCut and Premiere Pro.
- [Universal Thumbnail Downloader](https://altrepo.net/social/thumbnail-downloader.html): Download high-quality thumbnails from YouTube, TikTok, and Vimeo instantly. Free, no watermark, fast extraction tool.
- [YouTube Thumbnail Preview & Tester](https://altrepo.net/social/youtube-thumbnail-preview/): Free YouTube thumbnail preview and tester. Compare titles and thumbnails in desktop, mobile, sidebar, and Shorts mockups before you publish.
- [YouTube Timestamp Generator](https://altrepo.net/social/youtube-timestamp-generator.html): Free YouTube timestamp generator: make a timestamp link, a short link, a comment timestamp, an embed link, and a description-ready chapter list. Runs in your browser.

## Text

Count, convert, compare, and clean text in your browser.

- [Case Converter](https://altrepo.net/text/case-converter.html): Paste your text once, then copy it back in any case: UPPERCASE, camelCase, snake_case, small caps and more. Free, instant, and it all happens in your browser.
- [Fancy Text Generator](https://altrepo.net/text/fancy-text/): Free fancy text generator. Type once and copy and paste bold, italic, script, fraktur, and dozens more cool Unicode fonts for Instagram, WhatsApp, Discord, and more.
- [Lorem Ipsum & Dummy Text Generator](https://altrepo.net/text/lorem-ipsum-generator.html): Free online dummy text generator. Instantly create 1000 characters sample text, words, paragraphs, or lists. Features a one-click copy paste utility.
- [Rich Text Editor](https://altrepo.net/text/rich-text-editor/): Free online rich text editor. Paste from Word or Google Docs, strip the messy formatting, then export clean HTML, Markdown, plain text, Word, or PDF. Everything runs in your browser.
- [Text Cleaner](https://altrepo.net/text/text-cleaner/): Clean up pasted text with one-click operations like trim, remove blank lines, dedupe, sort, join lines, and Unicode cleanup. Processed locally in your browser.
- [Text Compare](https://altrepo.net/text/text-compare/): Free online text compare and diff checker. Paste two texts or two lists, then highlight every addition and deletion. Line or word diff, ignore case or extra spaces, all in your browser.
- [Word Counter](https://altrepo.net/text/word-counter/): Paste text to instantly count words, characters (with or without spaces), sentences, paragraphs, and estimate reading time. Runs locally in your browser.