Unit Converter
Free online unit converter for length, weight, temperature, area and speed. Instant, accurate results that run entirely in your browser.
- ✓ Runs in your browser — nothing uploaded
- ✓ No sign-up
- ✓ Free, no limits
This free unit converter turns any measurement into another instantly — length, weight, temperature, area and speed — without installing anything or sending your data anywhere. Pick a category, choose the units to convert from and to, type a value, and the result updates as you type.
It covers the conversions people actually need every day: kilometres to miles for travel, pounds to kilograms for shipping and fitness, Celsius to Fahrenheit for weather and cooking, square metres to square feet for property listings, and km/h to mph for speed limits. Worked example: 10 km is 6.214 miles — the converter multiplies by each unit's exact factor to the base unit (a mile is defined as exactly 1,609.344 metres), so results are precise rather than rule-of-thumb approximations.
Everything runs locally in your browser using exact, internationally defined conversion factors. That means it works offline once the page has loaded, gives the same answer every time, and your numbers never leave your device. Bookmark it for quick access — and if you convert currencies or work out pay too, the related tools below have you covered.
Frequently asked questions
How do I convert km to miles?
Select the Length category, choose kilometres as the source unit and miles as the target, then type your value. One kilometre equals 0.621371 miles, so 10 km is 6.21 miles.
Is this unit converter accurate?
Yes. It uses exact, internationally defined conversion factors (for example one inch is defined as exactly 25.4 mm), so results are as precise as your input.
Does it work offline?
Yes. All conversions run in your browser with no server involved, so once the page has loaded you can keep converting without an internet connection.
Is my data uploaded anywhere?
No. Nothing you type leaves your device — the maths happens locally in your browser.