Convert between length, weight, volume, temperature, and more units.
The Unit Converter converts values across ten categories: length, weight and mass, temperature, volume, area, speed, time, digital storage, pressure and energy. Choose a category, pick two units and the result updates as you type, with a swap button and exact factors (US and imperial volume are marked separately).
Made for everyone. Typical uses:
Converting 5 kilometers gives 3.106855961 miles, 70 kilograms gives 154.3235835 pounds, and 98.6 °F converts to 37 °C. In volume, 1 US gallon is 3.785411784 liters while 1 imperial gallon is 4.54609 liters, which is why the units are labeled separately.
Conversions use standard international factors and are accurate for everyday use, but check the notes for ambiguous units: cups, pints and gallons default to US measures, a year is 365.25 days, and KB, MB and GB use decimal steps (KiB, MiB and GiB are the binary ones). For currency, use the Currency Converter.
Accuracy: Conversions use well-known methods and are tested with real sample inputs. Check the output before you send or publish it.
Expert Tip
Convert once from the original figure instead of chaining conversions, because rounding at each step adds up. For recipes, weigh dry ingredients in grams where you can, because a cup of flour varies with how it is packed.
The Unit Converter converts between units in ten categories: length, weight and mass, temperature, volume, area, speed, time, digital storage, pressure and energy. You pick a category with the buttons at the top, enter a value, choose the unit to convert from and the unit to convert to, and read the result. The swap button reverses the pair. Because each pair of drop-downs lists only the units of the chosen category, you cannot accidentally convert a length into a weight. A collapsible section under the result lists the same quantity in all the other units of the category at once.
Results show up to ten significant digits, with trailing zeros removed. These come from the converter itself.
Several units have more than one definition, and the converter labels them. Cups, pints, quarts, gallons and fluid ounces are US measures unless the label says imperial, and a US gallon is about 17 percent smaller than an imperial one. Some countries also use a 250 mL metric cup in recipes, which is not the same as a US cup. A US ton is 2,000 pounds, a UK long ton is 2,240 pounds and a metric tonne is 1,000 kilograms. A year is taken as 365.25 days. For digital storage, KB, MB, GB and TB count in thousands, while KiB, MiB, GiB and TiB count in 1,024s, so 500 GB is about 465.66 GiB, which is why a new drive looks smaller in the operating system.
Most units convert by multiplying, but temperature scales also have different zero points, so the converter uses formulas. Degrees Fahrenheit equal degrees Celsius multiplied by 9/5, plus 32, and kelvin is Celsius plus 273.15. That is why doubling a Celsius temperature does not double the Fahrenheit one. If you need only one conversion, the single-purpose pages are quicker: Celsius to Fahrenheit, Miles to Kilometers, Kilograms to Pounds, Inches to Centimeters and Feet to Meters.
Convert once from the original figure instead of chaining conversions, because rounding in each step adds up. Keep the value you were given, not a rounded copy. For cooking, weigh dry ingredients in grams where you can, because a cup of flour varies with how it is packed. For web design, the CSS Unit Converter handles pixels, rems and viewport units. Money is different, because exchange rates change daily, so use the Currency Converter for that.
The factors are the exact international definitions, such as 1 inch = 2.54 centimetres and 1 pound = 0.45359237 kilograms, so any difference you see comes only from rounding. Everything is calculated in your browser. Typing an invalid number shows a message instead of a result.
Explore more in Converters, read the guides and articles, or see how we test our tools.
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