Free Online Unit Converter
Free online unit converter for converting common measurements and units quickly and easily.
Unit Converter
Select a category and enter a value to convert it instantly.
How it works
- Choose a category such as length, weight or temperature.
- Pick the units to convert from and to.
- Type a value — the result updates instantly. Use the swap button to reverse.
Frequently asked questions
How accurate are the conversions?
Conversions use the exact definitions of each unit (for example 1 inch = 2.54 cm exactly) and are shown with sensible rounding. For engineering work, keep extra decimal places and round only at the end.
Why is temperature conversion different from other units?
Celsius, Fahrenheit and Kelvin have different zero points, so they need an offset as well as a multiplier: °F = °C × 9/5 + 32. Other units, like metres to feet, only need a multiplier.
What is the difference between US and imperial units?
Some units share names but differ in size. A US gallon is about 3.785 litres while an imperial (UK) gallon is about 4.546 litres. Check which system your recipe or specification uses.
Does the converter work offline?
Conversions happen in your browser, so once the page has loaded no internet connection is needed to convert.
What is a unit converter?
A unit converter helps you convert a measurement from one unit into another. For example, you can convert kilometres to miles, kilograms to pounds, litres to gallons or Celsius to Fahrenheit.
What can you convert?
This converter supports several common categories of measurement, including length, weight, temperature, area, volume, speed, time and digital data.
How to use the unit converter
- Select the type of measurement you want to convert.
- Select the unit you are converting from.
- Select the unit you want to convert to.
- Enter the value you want to convert.
Common unit conversions
- Kilometres to miles
- Miles to kilometres
- Kilograms to pounds
- Pounds to kilograms
- Celsius to Fahrenheit
- Litres to gallons
- Metres to feet
- Megabytes to gigabytes
Is this unit converter free?
Yes. This unit converter is completely free to use and does not require an account or registration.