Unit Converter
Convert between metric and imperial units in one place. Pick a category and units, then type in either box.
By Shah Rukh, software developer · Last updated:
What you can convert
| Category | Units |
|---|---|
| Length | millimeters, centimeters, meters, kilometers, inches, feet, yards, miles |
| Weight | milligrams, grams, kilograms, metric tons, ounces, pounds, stone |
| Temperature | Celsius, Fahrenheit, Kelvin |
| Volume | milliliters, liters, cubic meters, US teaspoons, tablespoons, fluid ounces, cups, pints, quarts, US and UK gallons |
| Speed | m/s, km/h, mph, knots, ft/s |
| Area | cm², m², km², in², ft², yd², acres, hectares, mi² |
Exact conversion factors
Since 1959, the inch has been defined as exactly 2.54 cm and the pound as exactly 0.45359237 kg. Every other imperial length and weight factor here comes from those two numbers, so results are exact rather than rounded.
Popular converters
cm to inches · kg to lbs · feet to meters · Celsius to Fahrenheit · km to miles · height in feet and cm
Frequently asked questions
Are US and UK gallons the same?
No. A US gallon is 3.785 liters and a UK (imperial) gallon is 4.546 liters, about 20% bigger.
How accurate are the conversions?
They use the official exact definitions, and results show up to 10 significant digits.
Can I convert negative temperatures?
Yes. Temperatures below zero convert correctly, for example −40 °C is exactly −40 °F.
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