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Quick unit converter
Length, weight, volume, area, speed and temperature with exact ISO/NIST factors. Converts live as you type.
Common values
Dedicated converters
Centimeters → InchesInches → CentimetersKilograms → PoundsPounds → KilogramsKilometers → MilesMiles → KilometersMeters → FeetFeet → MetersMillimeters → InchesInches → MillimetersMilliliters → Fluid ounces (US)Fluid ounces (US) → MillilitersGrams → OuncesOunces → GramsLiters → Gallons (US)Gallons (US) → LitersCelsius → FahrenheitFahrenheit → CelsiusKilometers per hour → Miles per hourMiles per hour → Kilometers per hourKilograms → StoneStone → KilogramsCups (US) → MillilitersTablespoons (US) → Milliliters
Height & weight
Frequently asked
Is one inch exactly 25.4 mm?
Yes — by international agreement since 1959, the inch is defined as exactly 25.4 millimetres.
How many kilometres is a mile?
Exactly 1.609344 km. The other direction: one kilometre is about 0.621 miles.
What is the Celsius to Fahrenheit formula?
°F = °C × 9⁄5 + 32. So 20 °C is 68 °F, and the two scales cross at −40.