Unit converter
Length, weight, temperature, area, volume and speed.
In every unit
- Millimetres
- 1 000
- Centimetres
- 100
- Kilometres
- 0.001
- Inches
- 39.3701
- Feet
- 3.2808
- Yards
- 1.0936
- Miles
- 0.000621
Choose a category, enter a value and pick the units. Alongside the answer you get the same value in every other unit in that category, which is often faster than converting one pair at a time.
How to use it
- Choose a category such as length or weight.
- Enter a value and pick the units to convert between.
- Read the result, or check the full list below it.
Why use this tool
Completely private
Everything runs inside your browser. Your files and text are never sent to a server.
Free, with no limits
No sign-up, no watermarks and no cap on how many times you can use it.
Instant results
There is no upload or queue to wait for, so results appear as fast as your device can work.
Works on any device
Runs in any modern browser on phone, tablet or desktop. Nothing to install.
Frequently asked questions
- Why is temperature handled differently?
- Because its scales have different zero points, so you cannot just multiply by a factor. Converting Celsius to Fahrenheit needs both a multiplication and an offset — which is why 0 °C is 32 °F rather than 0 °F.
- How accurate are the conversions?
- The factors are exact by definition where one exists — an inch is exactly 25.4 mm and a pound exactly 0.45359237 kg. Results are rounded for display only.
- Are gallons US or imperial?
- US. A US gallon is about 3.785 litres and an imperial gallon about 4.546, so they are not interchangeable — a recipe using imperial measures will come out roughly 20% short.
- What is a knot?
- One nautical mile per hour, about 1.852 km/h. It is used in aviation and shipping because a nautical mile corresponds to one minute of latitude.