Unit Converter — Length, Weight, Temperature, Volume and More
Convert between metric and imperial units instantly: length, weight, temperature, area, volume, speed, time and data. Exact conversion factors and a table of every unit.
100 cm = 39.370079 in
100 cm in every unit
| Millimetres | 1,000 mm |
| Centimetres | 100 cm |
| Metres | 1 m |
| Kilometres | 0.001 km |
| Inches | 39.370079 in |
| Feet | 3.2808399 ft |
| Yards | 1.0936133 yd |
| Miles | 0.00062137119 mi |
| Nautical miles | 0.0005399568 nmi |
Popular conversions
How to use the converter
Pick a category, choose the two units, and type a number into either box — the other box updates as you type, in either direction. The table below lists the same value in every unit of that category, which is handy when you're not sure which unit you'll need.
The conversions people need most
- Centimetres to inches — divide by 2.54. A 180 cm person is 70.9 inches, or 5 ft 10.9 in.
- Kilograms to pounds — multiply by about 2.2046. 70 kg is 154.3 lb.
- Celsius to Fahrenheit — multiply by 9/5 and add 32. 37 °C, body temperature, is 98.6 °F.
- Kilometres to miles — multiply by about 0.6214. A 10 km run is 6.2 miles, and a marathon is 42.195 km or 26.2 miles.
- Litres to gallons — divide by 3.785 for US gallons or 4.546 for UK gallons.
Metric and imperial in everyday life
Almost every country uses the metric system officially, but imperial units hang on in daily life. The United States uses them for nearly everything; the UK still uses miles for road distances, pints for beer and milk, and stones for body weight; and screens, tyres and pipes are sized in inches worldwide. That mix is why a converter remains one of the most-used tools online.
A note on months and years
Months and years don't have fixed lengths, so the time conversions use averages from the Gregorian calendar: a year of 365.2425 days and a month of 30.44 days. For an exact number of days between two real dates, use the days-between-dates calculator instead.
Frequently asked questions
How accurate are the conversions?
They use the exact international definitions: an inch is exactly 2.54 cm, a pound exactly 0.45359237 kg and a US gallon exactly 3.785411784 litres. Results are shown to 8–10 significant figures, far beyond what any everyday measurement needs.
Why are there US and UK pints and gallons?
Because they are different sizes. A UK (imperial) gallon is about 4.546 litres and a US gallon about 3.785 litres, so a UK gallon is roughly 20% larger. The same goes for pints. Recipes and fuel figures from the United States use the US measures.
What is the difference between MB and MiB?
A megabyte (MB) is 1,000,000 bytes, while a mebibyte (MiB) is 1,048,576 bytes (1024 × 1024). Drive manufacturers use the decimal units, and some operating systems report sizes in the binary ones — which is why a “1 TB” drive shows up as about 931 GiB.
How do I convert Celsius to Fahrenheit in my head?
Double the Celsius figure and add 30 for a quick estimate: 20 °C → about 70 °F. The exact formula is °F = °C × 9/5 + 32, so 20 °C is exactly 68 °F. The shortcut is closest between about 0 °C and 30 °C, the range most weather falls in.
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Open toolLast updated September 25, 2026