Free online tools that run in your browser

BrowserTools is a growing collection of 62 focused utilities, converters, validators, encoders, calculators, networking helpers and a few classic games. Each one does a single job well, with no signup and no clutter.

Whenever a task can run on your own machine, it does: the file you paste, drop or type never leaves your browser, and there is nothing to install. The handful of tools that genuinely need a server (DNS, ping, WHOIS) call a small backend that does only what you ask and stores nothing about you.

62 tools
100% in your browser
No signup
No tracking
Free & open in spirit

Calculators 6

Compound Interest & Savings Calculator

Project the growth of your savings with monthly contributions, compound frequency and inflation-adjusted results.

Date Calculator

Calculate age from a date of birth, find the interval between two dates, or add and subtract time from any date.

Loan Comparison Calculator

Compare up to three loans side-by-side: monthly payment, total interest and total cost.

Mortgage & Loan Calculator

Calculate monthly mortgage or loan payments and visualize the full amortization schedule.

Percentage Calculator

Calculate percentages every way: X% of Y, what % is X of Y, percent change, increase or decrease.

Tip Calculator & Bill Splitter

Compute tip amount and split a bill evenly between any number of people.

Converters 11

Bytes Converter (KB, MB, GB, TB)

Convert between bytes, KB/MB/GB/TB and KiB/MiB/GiB/TiB, both decimal (base 10) and binary (base 2).

Color Converter & Contrast Checker

Convert colors between HEX, RGB, HSL and HSV, plus WCAG contrast ratio checker.

CSV ↔ JSON Converter

Convert between CSV and JSON locally with custom delimiters and quoting, no upload, no limits.

EV Efficiency Converter (Wh/km, kWh/100km, mi/kWh, MPGe)

Convert electric vehicle efficiency between Wh/km, kWh/100km, mi/kWh and MPGe. Estimate range and charging cost.

Fuel Consumption Converter (L/100km, MPG, km/L)

Convert vehicle fuel economy between L/100km, US MPG, UK MPG and km/L, and estimate trip cost.

Number Base Converter (Binary, Octal, Decimal, Hex)

Convert numbers between binary, octal, decimal, hexadecimal and any custom base from 2 to 36.

Roman Numerals Converter

Convert between Arabic numbers and Roman numerals (1 to 3,999,999) with a vinculum-aware algorithm.

Temperature Converter (°C, °F, K)

Convert temperatures between Celsius, Fahrenheit, Kelvin and Rankine instantly.

Text Case Converter

Convert text to UPPERCASE, lowercase, Title Case, camelCase, snake_case, kebab-case, a URL slug and more, instantly in your browser.

Unix Timestamp Converter

Convert between Unix timestamps and human-readable dates in any timezone, with millisecond precision.

Unit Converter

Convert between common units of length, mass, temperature, time and digital storage.

Encoders 5

Base64 Encoder & Decoder

Encode and decode Base64 text or files locally in your browser.

Escape & Unescape Tool

Escape or unescape text for HTML, XML, JSON, JavaScript, CSV and URLs, locally in your browser.

Hash Generator (SHA-1, SHA-256, SHA-384, SHA-512)

Compute cryptographic hashes of text or files locally, SHA-1, SHA-256, SHA-384 and SHA-512.

JWT Decoder

Decode and inspect JSON Web Tokens locally, header, payload and expiry claims.

URL Encode / Decode

Percent-encode or decode URLs and query parameters, component-safe and full-URI modes.

Entertainment 9

2048, Sliding Tile Puzzle

Play 2048 in your browser. Slide tiles on a 4×4 grid, merge equal numbers, and reach the 2048 tile.

Breakout, Classic Brick Breaker

Play classic Breakout in your browser. Bounce the ball, smash bricks, and clear all levels.

Retro Game Emulator, Play ROMs in Browser

Play classic retro console games in your browser. Load a ROM file and start playing, NES, SNES, GBA, N64, Sega, and more.

Minesweeper, Classic Browser Game

Play the classic Minesweeper game in your browser. Three difficulty levels, flag mines, beat your best time.

Snake, Classic Browser Game

Play the classic Snake game in your browser. Eat food, grow longer, and avoid hitting walls or yourself.

Klondike Solitaire, Classic Card Game

Play classic Klondike Solitaire in your browser. Draw 1 or Draw 3, auto-move to foundations, no installation needed.

Sudoku, Classic Number Puzzle

Play Sudoku in your browser. Three difficulty levels, mistake tracking, timer, and a built-in solver.

Tetris, Classic Falling Blocks

Play classic Tetris in your browser. Rotate and place falling tetrominoes, clear lines, and beat your high score.

Typing Speed Test, WPM Tester

Test your typing speed online. Get your WPM and accuracy in 15, 30, or 60 seconds. No sign-up required.

Generators 7

Color Palette Generator

Generate complementary, analogous, triadic, tetradic, monochromatic and shade/tint palettes from any base color.

CSS Gradient Generator

Build linear, radial and conic CSS gradients with a live preview and copy-ready code.

Lorem Ipsum Generator

Generate placeholder Lorem Ipsum text, paragraphs, sentences, words or HTML lists.

Password & Passphrase Generator

Generate strong random passwords and memorable passphrases locally, fully customizable.

QR Code Generator

Generate QR codes for URLs, text, Wi-Fi credentials and contact cards. Download as PNG or SVG.

QR Code Scanner

Scan QR codes from your camera or an uploaded image, entirely in your browser.

UUID Generator (v1, v4, v7)

Generate RFC 4122 UUIDs in version 1, 4 or 7, single or in bulk, copy or download.

Images 3

Image Converter (PNG / JPG / WEBP)

Convert and resize images locally in your browser using the Canvas API. No uploads.

Image Compressor (JPG / WEBP / PNG)

Reduce image file size with adjustable quality, see before/after side by side.

Image Resizer, Resize Photos Online

Resize images by width, height or percentage, lock the aspect ratio and pick a fit mode. 100% in your browser, no uploads.

Misc 4

Diff Checker (Text Compare)

Compare two blocks of text line by line and see exactly what was added, removed or kept, entirely in your browser.

Random Picker, List, Coin, Dice, Number

Pick a random item from a list, flip a coin, roll dice, or generate a random number.

Stopwatch & Timer

Online stopwatch with lap times and a countdown timer with audible alarm, all in your browser.

Word & Character Counter

Count words, characters, sentences, paragraphs and reading time as you type, entirely in your browser.

Networking 6

DNS Lookup

Query DNS records (A, AAAA, MX, TXT, NS, CNAME, SOA, CAA) for any public domain.

IP Subnet Calculator (CIDR / IPv4)

Calculate network address, broadcast, mask, host range and total hosts from any IPv4 CIDR notation.

What's My IP, User Agent & Browser Info

See your public IP address, user agent, request headers and browser capabilities, instant lookup, no tracking.

TCP Port Check (Ping)

Check if a TCP port on a public host is open and measure connection latency.

User-Agent Parser

Parse a User-Agent string into browser, engine, OS and device information.

WHOIS Lookup

Look up the WHOIS registration data for any public domain, registrar, dates and nameservers.

PDF 7

Images to PDF

Combine PNG, JPG and WEBP images into a single PDF document, in your browser, no uploads.

Markdown to PDF Converter

Convert Markdown to a clean, printable PDF locally in your browser, with live preview and no uploads.

PDF Compress (Optimize Size)

Reduce the size of a PDF locally by re-saving it with object streams and stripping unused metadata.

PDF Merge, Combine PDFs Online

Merge multiple PDF files into one document, fully in your browser. Drag to reorder, no uploads.

Rotate PDF Pages

Rotate all or specific pages of a PDF by 90°, 180° or 270°, locally in your browser.

PDF Split, Extract or Separate Pages

Split a PDF into single pages or extract a custom page range, entirely in your browser, no uploads.

PDF to Images (PNG / JPG)

Convert each page of a PDF to PNG or JPG images, entirely in your browser.

Validators 4

JSON Validator & Formatter

Validate, format and minify JSON in your browser with detailed error locations.

Password Strength Checker

Test how strong a password is: entropy, estimated crack time and a clear checklist, all checked locally in your browser.

Regex Tester & Debugger

Test JavaScript regular expressions live with match highlighting, capture groups and replace preview.

XML Validator & Formatter

Validate and pretty-print XML in your browser using the DOMParser.

How these tools work

Most utilities here are client-side: the logic ships as a small JavaScript module that runs in your browser, so your text and files are processed locally and never uploaded. That keeps things fast, works offline once the page has loaded, and means a sensitive document (a PDF you need to split, an image you want to resize) stays on your device.

Every tool page includes a short explanation of what the tool does, worked context, and answers to common questions, so you can understand the format or technique, not just click a button. If a tool can ever give a wrong or surprising result for a particular input, we try to say so on the page.

Have an idea for a tool, spotted a bug, or got a result that looks off? Tell us on the contact page, feedback is how the catalogue improves. You can also read about who runs BrowserTools and our privacy approach.