Unit converter
Convert any unit to any other unit, instantly — no need to know which direction you're going. Length, weight, volume, area, temperature, energy and data size.
Why there are two kinds of mile
The inch, foot, yard and mile you learned in school (the "statute mile", 1609.344 m) are the same in the US and the UK — they were standardized internationally in 1959. The nautical mile (1852 m exactly) is a different, older unit still used in aviation and at sea, based on one minute of latitude. Mixing the two up is a common source of errors, so this converter keeps them separate.
US and UK volume units are not the same
Unlike length, US customary and UK imperial volume units genuinely differ: a US gallon (3.785 L) is smaller than a UK/imperial gallon (4.546 L), and the same goes for fluid ounces, pints and quarts. This converter keeps the US and UK versions of each as separate units so you don't accidentally mix them.
Why temperature is different from every other unit
Meters, pounds and gallons all start from the same zero, so converting is just multiplication. Temperature scales don't: 0 °C equals 32 °F, not 0 °F, so the conversion needs a formula (°F = °C × 9/5 + 32) rather than a single factor. Handy anchor points: water freezes at 0 °C / 32 °F, boils at 100 °C / 212 °F, and −40 is the one temperature where Celsius and Fahrenheit agree. Kelvin (science) and Rankine (US engineering) are included too — both start at absolute zero.
Calories on food labels are actually kilocalories
The "Calorie" on a food label (capital C, also written kcal) is 1000 small calories — so a 500-Calorie meal is 500 kcal, which is about 2092 kJ. European labels usually print both. The energy category here uses the thermochemical calorie (1 cal = 4.184 J exactly) and also covers Wh/kWh (electricity bills) and BTU (heating and air conditioning).
Why your hard drive looks smaller than the box said
Storage manufacturers use decimal prefixes (1 KB = 1000 bytes, ×1000 per step), while operating systems traditionally report binary ones (1 KiB = 1024 bytes, ×1024 per step). A "1 TB" drive is 1,000,000,000,000 bytes, but your OS may show it as about 909 GiB — nothing is missing, they're just different units. This converter keeps KB/MB/GB (decimal) and KiB/MiB/GiB (binary) as separate, distinct units instead of treating "MB" and "MiB" as interchangeable.
Why do I get slightly different numbers than other converters?
All conversions here use the internationally standardized definitions (e.g. 1 inch = 25.4 mm exactly, 1 UK gallon = 4.54609 L exactly). Any difference you see elsewhere usually comes from rounding, not a different definition.
Is my data sent anywhere?
No — this runs entirely in your browser with plain JavaScript. Nothing is uploaded.