Unit Converter

How to use the Unit Converter

1. 1

   Select a category

   Choose from Length, Weight, Temperature, Volume, Area, or Speed using the category buttons at the top.

2. 2

   Pick your units

   Select the unit you're converting from and the unit you're converting to from the two dropdowns.

3. 3

   Enter a value

   Type your number into the Value field. The result updates instantly as you type.

4. 4

   See all conversions

   A table below the result shows the same value converted into every available unit in that category — handy for quick comparisons.

About this Unit Converter

Unit conversion is one of the most common everyday calculations — from checking whether your luggage is within the weight limit, to converting a recipe from cups to millilitres, to understanding how fast a car is going in a foreign country. Despite the ubiquity of the metric system globally, the US still uses customary units and the UK uses a mix of both, making cross-unit conversions a daily need. The metric system (officially the International System of Units, or SI) was developed in France during the 1790s and is now used by every country in the world — with the notable exception of the US, Myanmar, and Liberia for everyday use. The metric system's elegance is its consistent use of powers of 10: a kilometre is exactly 1,000 metres; a kilogram is exactly 1,000 grams. Temperature is unique among units because conversion involves both multiplication and addition — not just scaling. This is because Celsius and Fahrenheit have different zero points. The Kelvin scale avoids this by starting at absolute zero (-273.15°C), making it the preferred scale in scientific contexts where negative temperatures would cause problems in formulas. Our converter uses exact conversion factors where they are defined by international standards (e.g., 1 inch = exactly 2.54 cm) and high-precision values for derived conversions.

Frequently Asked Questions