Free Unit Converter Online — Length, Weight, Temperature & More

I can never remember how many ounces are in a kilogram. Or how many feet make a meter. Every single time I need a unit converter, I end up on some ad-filled nightmare site that makes me click through three pages before showing me the answer.

That's why I built this free unit converter. You pick a category, enter your number, and get the result. No pages to click, no pop-ups, no nonsense.

What Units Can You Convert?

The unit converter covers all the common categories you'd actually need:

Length: meters, feet, inches, miles, kilometers, yards, centimeters
Weight: kilograms, pounds, ounces, grams, stones, tons
Temperature: Celsius, Fahrenheit, Kelvin
Volume: liters, gallons, cups, milliliters, fluid ounces
Speed: mph, km/h, knots, meters per second

Each conversion happens instantly as you type. No "calculate" button to press — you just see the results update in real time.

When This Actually Comes in Handy

I use this unit converter way more often than I expected. Cooking with a recipe from another country? Gotta convert cups to milliliters. Shopping online from a UK store? Need to know what "10 stone" means in pounds. Checking weather while traveling? Celsius to Fahrenheit, every time.

It's also super useful if you're a student working through physics or chemistry problems. Instead of hunting through textbooks for conversion factors, just punch in the numbers and move on to the actual problem.

Why Not Just Google It?

Google does have a built-in converter, and honestly it's fine for one-off conversions. But if you're doing several conversions in a row — like converting a whole recipe or comparing multiple measurements — having a dedicated tool with category tabs is just faster.

Plus, this works entirely in your browser. No data sent anywhere. If you're working offline or on a slow connection, it still works perfectly.

Tips for Accurate Conversions

A couple things worth knowing. Temperature conversions aren't linear like the others — going from Celsius to Fahrenheit uses a formula, not a simple ratio. The tool handles that for you, but it's worth understanding why 0°C isn't 0°F.

Also, be careful with "tons." There are metric tons (1,000 kg), short tons (2,000 lbs, used in the US), and long tons (2,240 lbs, used in the UK). The converter lets you pick which one you mean.

Need to convert some units right now? Try it free →