Unit converter
Pick a type of measurement, type a value and choose the units. The answer updates as you type, and a list below shows the same value in every unit of that type. Conversion factors are the exact definitions published by NIST, the US standards body.
Everything runs on your device. Nothing you add or type is sent to any server.
How to use it
- 01
Choose length, weight, area, volume, temperature, speed or data.
- 02
Type the value and pick the unit you have and the unit you want. Tap the swap button to reverse them.
- 03
Read the result, or scan the list to see the value in every other unit.
Exact factors, worked examples
Imperial and US units are defined exactly in metric terms: 1 inch is 2.54 cm, 1 foot is 0.3048 m, 1 mile is 1,609.344 m, 1 pound is 0.45359237 kg, 1 acre is 4,046.8564224 m², 1 US gallon is 3.785411784 litres and 1 UK gallon is 4.54609 litres. So a height of 5.5 feet is exactly 167.64 cm, 1 acre is 43,560 square feet, and 100 km/h is about 62.14 mph.
Temperature uses formulas instead of a single factor: °F = °C × 1.8 + 32, and K = °C + 273.15. For example, 37 °C is 98.6 °F. Values below absolute zero (0 K) are refused. Results are shown to 10 significant digits.
KB or KiB? Why your 1 TB drive shows 931 GB
In the metric (SI) system, kilo means 1,000, so 1 kB is 1,000 bytes and 1 GB is 1,000,000,000 bytes. Computer memory has long counted in powers of two, so kilo was also used to mean 1,024. To end the confusion, the IEC created binary prefixes: 1 KiB is 1,024 bytes, 1 MiB is 1,048,576 bytes, and so on. A 1 TB drive holds 1,000,000,000,000 bytes, which is about 931.32 GiB. Software that counts in powers of two but labels it GB will show about 931 GB. One byte is 8 bits.
Indian land units
Bigha and its local sub-units such as katha are not included, because the size of a bigha differs from state to state and sometimes between districts. Check the value used in your state's land records, then convert from square feet or square metres here.
Frequently asked questions
Is a US gallon the same as a UK gallon?
No. A UK (imperial) gallon is 4.54609 litres and a US gallon is 3.785411784 litres, so the UK gallon is about 20 % larger.
Why can't I enter a negative length?
Lengths, weights, areas, volumes, speeds and data sizes here are sizes, so they can't be negative. Temperatures can be negative, down to absolute zero.
Does it work offline?
Yes, once the page has fully loaded. Conversions run in your browser, so they keep working if your connection drops, and nothing is sent anywhere.