Unit Converter
Length, weight, temperature, area, volume, speed, data, pressure, energy and more.
How to use Unit Converter
- Choose the kind of quantity.
- Enter the value and pick the units to convert from and to.
- Read the result and the full table of every unit in that category.
How it works
Conversions use exact definitions wherever they exist: 1 inch = 2.54 cm and 1 pound = 0.45359237 kg (the 1959 international yard and pound), 1 US gallon = 3.785411784 L, 1 UK gallon = 4.54609 L, 1 mile = 1,609.344 m. Temperature uses the offset formulas (°F = °C × 9/5 + 32; K = °C + 273.15), and fuel economy converts between distance-per-volume and L/100 km, which are reciprocals.
Data sizes are shown in both decimal units (kB, MB, GB: powers of 1000, used by drive makers and networks) and binary units (KiB, MiB, GiB: powers of 1024, used by many operating systems), which is why a "1 TB" drive shows about 931 GiB.
Example
1 mile = 1.609344 km exactly. 100 °C = 212 °F. 10 L/100 km ≈ 23.5 mpg (US).
Frequently asked questions
Why does my 1 TB drive show 931 GB?
The drive uses decimal terabytes (10¹² bytes); the operating system often reports binary gibibytes (2³⁰ bytes) but labels them "GB". 10¹² ÷ 2³⁰ ≈ 931.
Which cup is used?
The US legal cup (240 mL), used on US nutrition labels. A US customary cup is about 236.6 mL and a metric cup is 250 mL.
Are US and UK gallons the same?
No: a US gallon is 3.785 L and a UK (imperial) gallon is 4.546 L, so mpg figures differ too.
How precise are the results?
Calculations use full double precision; results are displayed with up to 10 significant digits.
Limitations
- Display precision is limited to 10 significant digits.
- Currency conversion is not included (it needs live exchange rates).
Last reviewed November 9, 2026. How we build and test tools.