Unit Converter
Convert between metric and imperial units instantly: length, weight, temperature, volume and speed. Every result shows the formula used, so you can check it.
1 km = 0.621371192237 mi
Formula: mi = km × 0.621371192237
1 km in every unit
| Millimetre | 1,000,000 mm |
|---|---|
| Centimetre | 100,000 cm |
| Metre | 1,000 m |
| Inch | 39,370.0787402 in |
| Foot | 3,280.83989501 ft |
| Yard | 1,093.61329834 yd |
| Mile | 0.621371192237 mi |
| Nautical mile | 0.539956803456 NM |
How to convert units
Choose the type of measurement: length, weight, temperature, volume or speed.
Type the value and pick the unit you are converting from and the unit you want. You can use a point or a comma as the decimal separator.
The result appears as you type. Use the swap button to reverse the conversion, or open the list to see the value in every unit at once.
Common conversions
Kilometres to miles
1 km = 0.621371 mi, and 1 mile is exactly 1.609344 km. A 10 km race is about 6.21 miles.
Kilograms to pounds
1 kg ≈ 2.204623 lb, and 1 pound is exactly 0.45359237 kg. So 70 kg is about 154.3 lb.
Celsius to Fahrenheit
Multiply by 9/5 and add 32: 20 °C = 68 °F and 37 °C = 98.6 °F. −40 is the same in both scales.
Litres to US gallons
1 US gallon is exactly 3.785411784 litres. The UK (imperial) gallon is larger: 4.54609 litres.
How the conversions are calculated
Length, weight, volume and speed are linear: each unit is stored as an exact multiple of a base unit (metre, kilogram, litre or metre per second), and the value is converted to the base unit and then to the target unit. The factors are the official definitions, such as 1 inch = 2.54 cm, 1 pound = 0.45359237 kg and 1 US gallon = 231 cubic inches.
Temperature scales have different zero points, so they can't be converted with a single factor. The converter uses the exact formulas, going through kelvin: °C = K − 273.15 and °F = °C × 9/5 + 32. Values below absolute zero (0 K, −273.15 °C or −459.67 °F) are flagged, because no temperature can be lower.
Results are shown with up to 12 significant digits, very large or very small numbers switch to scientific notation, and tiny rounding errors from binary arithmetic are removed. US and UK units with the same name, such as gallons and pints, are listed separately because they are different sizes.
Frequently asked questions
What is the difference between US and UK gallons?
A US gallon is 3.785411784 litres and a UK (imperial) gallon is 4.54609 litres, about 20% more. US and UK pints differ in the same way. Recipes and fuel figures from the US use US units.
Is weight the same as mass?
Strictly, kilograms and pounds measure mass, and weight is the force of gravity on that mass. In everyday use, "weight" means mass, which is what this converter calculates.
How do I convert Fahrenheit to Celsius in my head?
Subtract 30 and halve the result for a quick estimate: 80 °F is about 25 °C (exactly 26.7 °C). For an exact result, subtract 32 and multiply by 5/9.
What is a knot?
A knot is one nautical mile per hour, exactly 1.852 km/h. It is used in aviation and at sea because nautical miles are based on the Earth's latitude.
Can I type decimals with a comma?
Yes. Both 1.5 and 1,5 are read as one and a half. Thousands separators also work, for example 1,000.5 or 1.000,5.