Which units can I convert between?

Length, weight, volume, area, speed, data storage, pressure, time and temperature — nine categories with the common units of each. Conversions only work within a category, since converting kilograms to metres is not a meaningful question.

Why is temperature handled differently?

Because Celsius, Fahrenheit and Kelvin do not share a zero point. Every other conversion is a single multiplication; temperature needs a scale factor and an offset, so doubling a Celsius value does not double the Fahrenheit one.

Are the conversions exact?

Where the definitions are exact, yes — an inch is precisely 25.4 millimetres and a pound precisely 0.45359237 kilograms by international agreement. Displayed values are rounded for readability, but the underlying arithmetic is not.

Can I convert between metric and imperial?

Yes, in both directions and within every category. The units are listed together rather than split by system, so metres and feet sit in the same dropdown.

Is there a page for a specific conversion?

Yes. Common conversions such as pounds to kilograms or Celsius to Fahrenheit have their own pages with the formula written out and a table of typical values, which is often quicker than setting up the dropdowns.

Unit Converter

Every measurement in one place — length, weight, temperature, volume, area, speed, data and time.

UnitsRuns in your browserFree, no signup

About the Unit Converter

One place for every measurement type — length, weight, volume, area, speed, data, pressure, time and temperature. Pick a category and the units for it appear; values convert as you type in either direction.

Every conversion goes through a base unit rather than storing a factor for each pair. That is why the numbers agree in both directions and why round-tripping a value returns exactly what you started with, which a table of hand-entered pair factors reliably fails to do.

Temperature is handled separately from everything else, because it is the one measurement where the scales do not share a zero. Converting it needs an offset as well as a factor, so it cannot use the same code path as the multiplicative units.

How it works

Pick a category — length, weight, temperature, and so on.
Type a value and choose the units to convert from and to.
The result updates instantly, with the same value shown in every other unit below.

Frequently asked questions

Which units can I convert between?: Length, weight, volume, area, speed, data storage, pressure, time and temperature — nine categories with the common units of each. Conversions only work within a category, since converting kilograms to metres is not a meaningful question.
Why is temperature handled differently?: Because Celsius, Fahrenheit and Kelvin do not share a zero point. Every other conversion is a single multiplication; temperature needs a scale factor and an offset, so doubling a Celsius value does not double the Fahrenheit one.
Are the conversions exact?: Where the definitions are exact, yes — an inch is precisely 25.4 millimetres and a pound precisely 0.45359237 kilograms by international agreement. Displayed values are rounded for readability, but the underlying arithmetic is not.
Can I convert between metric and imperial?: Yes, in both directions and within every category. The units are listed together rather than split by system, so metres and feet sit in the same dropdown.
Is there a page for a specific conversion?: Yes. Common conversions such as pounds to kilograms or Celsius to Fahrenheit have their own pages with the formula written out and a table of typical values, which is often quicker than setting up the dropdowns.

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