Unit converter

Length, weight, temperature and more - live conversion.

One converter for everything

Choose a category, enter a value, then the units to convert from and to: the conversion is instant.

Category	Example units
Length	millimetre, centimetre, metre, kilometre, inch, foot, yard, mile
Weight	milligram, gram, kilogram, tonne, ounce, pound
Temperature	Celsius, Fahrenheit, Kelvin
Volume	millilitre, litre, cubic metre, cup, US pint, US gallon
Speed	km/h, m/s, mph, knot
Area	m², are, hectare, km², square foot, acre

Useful benchmarks

1 inch = 2.54 cm exactly; 1 foot = 30.48 cm; 1 mile = 1.609 km.
1 pound = 453.6 g; 1 ounce = 28.35 g.
1 hectare = 10,000 m², a square 100 m on each side, or about 2.47 acres.
1 knot = 1.852 km/h, one nautical mile per hour.
100 km/h ≈ 27.8 m/s ≈ 62 mph.

Temperature is a special case

Temperatures cannot be converted by simple multiplication, because the scales do not share the same zero. The tool uses the dedicated formulas:

Celsius to Fahrenheit: °F = °C × 9/5 + 32
Fahrenheit to Celsius: °C = (°F − 32) × 5/9
Celsius to Kelvin: K = °C + 273.15

Benchmarks: 0 °C = 32 °F (water freezes), 37 °C = 98.6 °F (body temperature), 100 °C = 212 °F (water boils). −40 is the only value that is the same in Celsius and Fahrenheit.

Beware of units with the same name

Several units share a name but not a value. The gallon used by the converter is the US gallon, about 3.785 litres, whereas the imperial (UK) gallon is about 4.546 litres; the same goes for the pint. The land mile is 1,609 m, the nautical mile 1,852 m. The metric tonne is 1,000 kg, the US "short ton" about 907 kg. If you are unsure where a figure comes from, check which unit is meant.

Rounding

Results are shown with enough precision for everyday life. For technical or scientific use, keep rounding in mind and double-check critical conversions.

Frequently asked questions

How many units are supported?

Dozens, across six categories: length, weight, temperature, volume, speed and area.

Why doesn't temperature convert like other units?

Because Celsius, Fahrenheit and Kelvin do not share the same zero point. It takes a formula with an addition, not just a factor.

Is the gallon US or imperial?

The converter uses the US gallon, about 3.785 L. For imperial gallons (4.546 L), multiply the result in US gallons by about 0.833.

Is the conversion done online?

No, everything is calculated in your browser.