About ChangingUnits
A free unit converter that covers the conversions other sites miss — from BTU to kilojoules, PSI to bar, smoots to football fields, and 1,500 more.
What ChangingUnits does
Type a number and get an answer — no button press, no page reload, no signup. Every converter updates instantly as you type, works on any device, and shows a quick-reference table so you can scan common values without doing the calculation yourself.
The categories cover what people actually search for: the standard ones (length, weight, temperature, area, volume, speed) plus the ones Google's built-in converter doesn't handle — energy, pressure, fuel economy, data storage, angles, frequency, and time. There's also a fun units section for the more unusual requests: smoots, blue whales, lightsabers, and a few others.
Accuracy and sources
Every conversion factor comes from an internationally recognised definition. SI units follow the NIST SI reference. Imperial and US customary units use the exact statutory definitions (one inch = 25.4 mm exactly, one pound = 0.45359237 kg exactly, and so on). Where US and UK measurements differ — gallons, pints, tons — we label clearly which standard is being used.
If you find something that looks wrong, please let us know. We check every report.
No clutter, no tricks
The converter is the first thing on every page. There's no interstitial, no cookie wall, no "download our app" banner. The site is built as static HTML — it loads fast, works offline after the first visit, and has no tracking beyond standard Google Analytics.
Get in touch
Questions, errors to report, or units you'd like to see added — use the contact form or email [email protected] directly.