Free online tools that
just work.
Calculators, converters, generators. Everything runs in your browser — your data never leaves your device.
Create custom QR codes for URLs, text, Wi-Fi, contacts and more — free, no signup.
Create strong, random passwords with customizable length and character sets — runs offline.
Calculate your Body Mass Index in metric or imperial units — instant result, no signup.
Convert between metric and imperial units — length, weight, temperature, area, volume.
Convert colors between HEX, RGB, HSL, HSV, and CMYK — with live preview.
Format, validate, and minify JSON — with syntax error pinpointing.
Encode or decode Base64 strings — works for text and files.
Percent-encode or decode URLs and query parameters — full and component modes.
Count words, characters, sentences, paragraphs, and estimated reading time.
Convert times across cities — schedule meetings across timezones effortlessly.
Calculate your exact age in years, months, days, hours, and minutes.
Compute percentages, increases, decreases, tips, and percentage-of-total — six modes.
What is BoxTool?
BoxTool is a collection of free, single-purpose utilities for the small tasks that interrupt your day: formatting a blob of JSON, converting an image, calculating a loan payment, generating a strong password. Instead of installing an app or signing up for a service, you open the tool, use it, and move on.
Nearly every tool runs entirely in your browser. Your files, passwords, and text are processed on your own device and never uploaded to our servers — which also makes the tools fast and usable offline once loaded. Each tool page includes a practical guide covering how it works, common use cases, and the mistakes to avoid.
Every tool is hand-built and tested before release — you can read about our methodology on the about page. For longer walkthroughs, see our guides.