Unit Converter

Convert between units of length, weight, temperature, and more

Foot (ft)

3.2808399

1 Metre (m) in all units

Kilometre (km)

Centimetre (cm)

Millimetre (mm)

Mile (mi)

Yard (yd)

Foot (ft)

Inch (in)

Nautical Mile

About the Unit Converter

This unit converter handles length, weight, temperature, volume, speed and time, converting between metric and imperial units as you type, in both directions. Conversion factors are held at full precision rather than rounded, so converting a value and converting it back returns the number you started with.

A unit converter is needed most often between the metric and imperial systems: a recipe in cups, a height in feet and inches, a package weight in pounds, an oven temperature in Fahrenheit, or a speed limit in miles per hour.

Every category converts in both directions and updates as you type, so there is no submit step and no need to know which way round the factor goes. Temperature is handled with its proper formulas rather than a multiplier, since Celsius and Fahrenheit have different zero points — the common source of wrong answers.

Factors are stored at full precision, so converting inches to centimetres and back returns the number you started with instead of drifting. Everything runs in your browser.

How to use the Unit Converter

  1. Pick a category. Choose length, weight, temperature, volume, area or speed.
  2. Choose your units. Select the unit you have and the unit you want.
  3. Enter the value. Type the amount. The converted figure appears immediately.
  4. Switch direction. Swap the units to convert the other way.

Unit Converter features

  • Length, weight, temperature, volume, speed and time
  • Metric and imperial in both directions
  • Converts as you type
  • Factors held at full precision, so round trips are exact
  • Copy any converted value
  • Runs in your browser; nothing is uploaded

Frequently asked questions

Which categories are covered?

Length, weight, temperature, volume, speed and time, each with the metric and imperial units in common use — kilometres through to nautical miles, grams through to stones, and Celsius, Fahrenheit and Kelvin.

Why is temperature different from the other conversions?

Because its scales have different zero points, so it needs an offset as well as a factor. That is why 0°C is 32°F rather than 0°F, and why you cannot convert a temperature by multiplying alone.

How accurate are the conversions?

Factors are stored at full precision and rounding happens only for display, so converting a value across and back returns your original number rather than something a fraction out.

Does it keep a history of my conversions?

No. Each conversion replaces the last and nothing is stored, so reloading the page starts fresh.

Which is heavier, a US or an imperial measure?

It depends on the unit, which is exactly the trap. A US gallon is about 3.79 litres and an imperial gallon about 4.55 — a 20% difference that quietly ruins recipes and fuel-economy comparisons.