AZ Tools
A free collection of fast, private tools that run right in your browser.
AZ Tools is a collection of 643 free tools that run in your web browser: calculators for everyday numbers, unit and date converters, text counters, and utilities for images, PDFs and code. There is nothing to install and no account to create.
The tools run on your own device. The text you type and the files you open are processed by the page itself and never uploaded to our servers, so you can use them with documents you would rather keep to yourself.
Calculations are checked against published reference values — official test vectors, exact unit definitions, codes known to be valid — and every tool is tested in a real browser before it goes live. If you spot a wrong answer, tell us and we will fix it.
Popular tools
For the jobs that come up every day: counting, calculating, converting, and working with images and PDFs.
Character & Word Counter
Count characters, words, sentences, lines, and bytes in real time.
Percentage Calculator
Work out percentages, what-percent, and percent change in one place.
QR Code Generator
Create custom QR codes from any text or URL and download them.
Image Compressor
Compress and resize JPEG, PNG, and WebP images in your browser.
Password Generator
Generate strong, random passwords that never leave your browser.
PDF Merger
Drop two or more PDFs, reorder them with the arrow buttons, and download a single merged PDF — all in your browser, no upload.
Image → PDF Converter
Combine multiple JPG / PNG images into a single PDF with adjustable page size, orientation, and fit.
Unit Converter
Convert length, weight, temperature, area, volume, speed, and time.
Age Calculator
Calculate exact age in years, months, days — and find your next birthday.
Date Calculator
Add or subtract years, months, weeks, days, and business days from any date — or find the difference between two dates.
JSON Formatter & Validator
Format, beautify, minify, and validate JSON right in your browser.
BMI Calculator
Calculate Body Mass Index from height and weight, with a healthy range.
Timezone Converter
Convert a date and time between any two world timezones, including DST.
Image Resize
Resize an image to any dimensions and export as PNG, JPEG, or WebP — all in your browser.
Stopwatch & Timer
A precise stopwatch with laps and a countdown timer with an alarm.
Loan / Mortgage Calculator
Calculate the monthly payment, total interest, and full amortization schedule for any fixed-rate loan.
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Guides
All guidesLonger articles on the problems behind the tools, and how to avoid them.
Why In-Browser Tools Keep Your Data Private
How client-side tools work, why running entirely in your browser means your data never leaves your device, and how to verify that claim yourself.
Passwords and Passphrases: What Actually Makes One Strong
Why length beats symbol substitution, where password strength meters mislead, how passphrases work, and what two-factor authentication does and does not protect.
Compressing and Resizing Images for the Web
How to make images small without making them look bad: resize before you compress, pick the right format, and understand what a quality slider actually does.
Why your photos rotate when you upload them
A photo looks upright on your phone, then lands sideways on the website you uploaded it to. The pixels never moved: the camera stored the picture the way the sensor read it and attached a note saying which way is up, and not every program reads that note.
Why your QR code won't scan on some phones
It works on your desk and fails on the poster. QR codes are read by finding three corner squares in a clean margin, and most scanning failures are a margin, a contrast or a size problem rather than anything wrong with the data inside.
Why Excel breaks your CSV, and how to stop it
Leading zeros vanish, long order numbers lose their last digit, and product codes turn into dates. None of it is a bug: it is Excel guessing a type for every field as it opens the file.