Metric ↔ US converter
Convert between metric and US customary units - length, weight, temperature, volume, cooking, speed and area. All instant, nothing uploaded.
Files are processed in your browser and never uploaded.
How to use Metric ↔ US converter
Enter your figures
Fill in Kilometres → Miles in km, Kilometres → Miles in mi, Metres → Feet in m and Metres → Feet in ft. Values you change are used straight away, with no submit button.
Adjust the assumptions
Fine-tune Metres → Yards in m, Metres → Yards in yd, Centimetres → Inches in cm and Centimetres → Inches in in to match your own situation.
Read the results
The Kilometres → Miles, Metres → Feet and Metres → Yards update as soon as a value changes.
What this tool does
Length, both directions
Kilometres and miles, metres and feet or yards, centimetres and inches, millimetres and inches, each pair converting either way.
Type into whichever box you have
Every conversion is a pair of boxes. Type into one and the other follows, so you never have to work out which way round it goes.
Weight and mass
Kilograms and pounds, grams and ounces, tonnes and US tons, which covers parcels, recipes and freight alike.
Temperature
Celsius and Fahrenheit, with the offset handled properly rather than treated as a simple ratio the way a quick multiplication would.
Volume
Litres and gallons, millilitres and fluid ounces, using US measures, which are not the same as imperial ones.
Runs fully in your browser with no upload and no sign-up
Every conversion is arithmetic done in your browser, so nothing is uploaded and the page works with no connection.
Frequently asked questions
Why doesn't the US use metric?
The US came close - the Metric Conversion Act of 1975 made metric the preferred system, and the Omnibus Trade and Competitiveness Act of 1988 made it the official system for federal agencies. But voluntary adoption meant most everyday use never switched, and the US remains one of only three countries (with Myanmar and Liberia) not officially metric in daily life.
What is the difference between US and imperial fluid ounces?
A US fluid ounce is 29.5735 ml; an imperial fluid ounce is 28.4131 ml - about 4% smaller. A US gallon is 3.785 litres; an imperial gallon is 4.546 litres. Always check which system a recipe or specification uses.
How do I quickly convert Celsius to Fahrenheit in my head?
Double the Celsius temperature, subtract 10%, then add 32. For example: 20°C → 40 − 4 + 32 = 68°F. The exact formula is F = C × 9/5 + 32.
Is my data uploaded anywhere?
No. All conversions run in your browser using exact formulas. Nothing is sent to a server.
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