Unit converter
Pick a category, type a value, and see the result instantly. You can type in either field and see the same value in every unit of the category.
Enter a value to convert it.
How it is calculated
- Formula
—- With your values
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The same value in all units
How to use it
- Choose a category, such as length, weight, or temperature. If you are not sure which one, search for the unit by name: “inches”, “pounds”, or “cup”.
- Type the value in either field: the other one is calculated as you type.
- Change the units with the selectors, or use the swap button. The shortcuts cover the most common conversions, like miles to km or °F to °C.
- Copy the result, or look in the table for the same value in every unit of the category. Select a unit name to use it as the destination.
Frequently asked questions
How many centimeters are in an inch?
An inch is exactly 2.54 centimeters by international definition. To convert inches to centimeters, multiply by 2.54; to convert centimeters to inches, divide by 2.54.
How do I convert Fahrenheit to Celsius?
Subtract 32 from the Fahrenheit temperature and multiply by 5/9: 212 °F is 100 °C. In the other direction, multiply the Celsius temperature by 9/5 and add 32. Temperature cannot be converted with a single factor, so the tool uses these formulas.
Why is 1 KB not always 1,024 bytes?
There are two conventions. The decimal kilobyte (KB) is 1,000 bytes and is what drive makers use. The kibibyte (KiB) is 1,024 bytes and is what many operating systems show as “KB”. Both are here: 1 GiB is 1,073,741,824 bytes.
Are U.S. and U.K. gallons and cups the same?
No. A U.S. gallon is 3.785 liters and an imperial (U.K.) gallon is 4.546 liters, so miles per gallon differ too. A U.S. cup is about 237 mL, while many recipes outside the U.S. use a metric cup of 250 mL, a tablespoon of 15 mL, and a teaspoon of 5 mL. All of them are included, so pick the one your recipe uses.
How precise is the result?
The factors are the exact ones from each definition, and the result is shown with 8 significant figures, which you can change under “Precision”. The whole-number part is never cut off, and only very large or very small values are written in scientific notation.
How do fuel economy figures compare?
Liters per 100 km measure how much a vehicle uses, while km/L and miles per gallon measure how far it goes. That is why the numbers move in opposite directions: 10 km/L is 10 L/100 km, and 20 km/L is 5 L/100 km.
Most searched conversions
- 1 inch = 2.54 cm · 1 foot = 30.48 cm · 1 mile = 1.609344 km.
- 1 pound = 0.45359237 kg · 1 ounce = 28.349523125 g.
- 32 °F = 0 °C · 212 °F = 100 °C · 0 °C = 273.15 K.
- 1 U.S. gallon = 3.785411784 L · 1 U.S. cup = 236.5882365 mL.
Exact units
Imperial and U.S. customary units are now defined from the metric system: the inch is exactly 25.4 mm and the pound is exactly 0.45359237 kg. That is why the factors in this tool are exact and not approximations. If you already have your weight and height in metric units, the BMI calculator in kilograms and centimeters takes them as they are.
KB, KiB, and the space on your drive
A 1 TB drive from a manufacturer holds 1,000,000,000,000 bytes, but an operating system that counts in powers of 1,024 shows it as about 931 GiB. Nothing is missing: it is the difference between the two conventions.
Tips
- Use the search box if you do not know which category a unit belongs to.
- For recipes, check whether the cup is a U.S. cup (237 mL) or a metric cup (250 mL) before converting.
- Need a weight in pounds for a health check? Try the BMI calculator, which accepts pounds, feet, and inches.
- Copy the link to come back to the same conversion.
Updated on September 29, 2026