Unit Converter
Length, weight, volume, area, speed, pressure and more.
Unit Converter handles length, mass, volume, area, speed, temperature, pressure, energy, power, angle, fuel economy and data in one place, with exact SI factors and the ability to convert one value into every unit of its family at once. It works offline once the page has loaded.
Loading Unit Converter…
Runs entirely on your device. No file or text you enter here is uploaded. How to verify it.
How to use Unit Converter
- Pick a category such as length or weight.
- Type a value and choose the units.
- Read the result, or the full table of every unit in that family.
Questions about Unit Converter
How precise are the conversions?
Exact where the definition is exact — one inch is precisely 25.4 mm, one pound is precisely 0.45359237 kg, both by international agreement. Everything else is computed in double precision and displayed with the significant figures you choose.
Why do US and UK gallons differ?
They are different units with the same name. A US liquid gallon is 3.785 litres, an imperial gallon is 4.546 litres — a 20% gap that ruins recipes and fuel economy comparisons. Both are listed separately.
Does it convert fuel economy correctly?
Yes, and note that MPG and litres per 100 km are inversely related, so you cannot convert them with a multiplier. The tool inverts properly instead of scaling.
Can I see every unit at once instead of picking a pair?
Yes. Under the single result there is a table of every unit in the chosen family, converted from the same input. It is the quicker route when you are not sure which unit the other person meant — nautical miles or statute, US or imperial fluid ounces.
Does it work on a phone with no signal?
Yes. The conversion factors are part of the page, so once it has loaded there is nothing left to fetch. The site also caches pages you have opened, so a tool you used before will still load on a plane or underground.
Is Unit Converter really free, with no limits?
Yes. There is no account, no daily cap, no file-size tier and no watermark, because there is no server cost to recover. The site is funded by clearly disclosed partner recommendations on the Partners page, never by metering the tools.
Are my files or text uploaded when I use Unit Converter?
No. Everything is processed by JavaScript running in your browser, on your device. You can verify it: open your browser's developer tools, switch to the Network tab, and use the tool. You will see no request carrying your data — because there is nowhere for it to go.