Free online tools that run in your browser

How these tools work

Each tool is a plain web page with its own address under toolsare.us. Favourites and share links use that path (for example /wordcount/). Older tool subdomains still open the same pages via redirect, so existing bookmarks keep working.

If a feature needs the network — loading a YouTube player, or storing a shared room ID — the page will say so. Otherwise you can work offline once the page has loaded, subject to what your browser allows.

Guides

Alongside the tools there is a library of twelve reference articles explaining the subjects underneath them — written to be worth reading on their own, not as documentation. They cover mechanisms rather than buttons, and where common advice is wrong they explain why rather than repeating it.

Codes and data: how a barcode actually encodes a number, including the hidden thirteenth digit; how a QR code survives being damaged, and why a logo in the middle works; the rules of JSON and where it bites, including the large numbers it silently corrupts.

Files and images: why compressing an image loses quality and the step that saves more than the quality slider ever will; what a PDF really is, and why merging is free while compressing is not.

Security and fairness: what actually makes a password hard to guess, with the entropy maths worked through; what “random” means for a computer, and why the usual way to shuffle a list is biased; what “runs in your browser” means and how to verify the claim yourself in thirty seconds.

Measurement: why time zones are harder than they look, including the hour that happens twice every year; the units that are not what you think — two gallons, three tons, and a temperature you cannot double; how colour works on a screen and why contrast is not obvious; why typing and reaction tests disagree with each other.

Browse all guides →

Why ToolsAre.Us exists

People should not need to install a heavy app for a five-minute job: counting words, converting units, making a QR code, or checking JSON. This hub keeps those utilities free, fast to open, and honest about privacy. Most tools never leave your device. A few shared tools (rooms, RSVPs, shared countdowns) store only what is needed to make a link work for other people — and they say so on the page.

What you can do here

Browse the full grid below for generators, converters, PDF helpers, timers, typing and reaction tests, colour tools, a notepad, speech tools, and more. Each tool has its own page with instructions, examples, limitations and a short FAQ. Subdomain bookmarks such as paint.toolsare.us still open the matching tool via redirect.

Advertising and cookies

The site may show ads so hosting can stay free. On your first visit we ask you to accept or decline non-essential cookies. Details are in the Privacy Policy. Essential preferences such as light/dark theme may still be stored so the UI works as expected.

Feedback

Found a bug? Use the contact page and include the tool name, browser, and what went wrong. Have an idea for a tool we do not have yet? Use the suggest a tool form — name, email, and what you need — and we will try to build useful ideas and get back to you.

Editorial standards

We write tool pages in plain English with real examples and honest limits. We do not invent user counts, awards or fake reviews. Structured data on tool pages describes the free browser application and frequently asked questions without aggregate ratings. If something is wrong, the contact page is the fastest way to tell us.

Using the tools safely

Do not paste passwords, private keys or confidential documents into tools unless you understand whether that tool stays local or uses a server. Password generation and most converters are local. Watch Together rooms, RSVP lists and shared countdowns store link state on the server so other people can open them — treat those links like invites.