Length & distance converter
cm to in — convert centimetres to inches
Exact 1 ÷ 2.54 = 0.39370079
Convert metres, feet, inches, miles, kilometres and more. Every imperial figure here is exact by definition, not rounded.
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Read the length unit guide — what each one is, where it came from, and which of them are quietly different from each other.
Questions
Is an inch exactly 2.54 centimetres?
Yes, exactly. Since 1959 the international inch has been defined as 25.4 millimetres, so the figure is a definition rather than a measurement. Every foot, yard and mile figure on this page follows from it and is equally exact.
Why is a nautical mile different from a mile?
It is tied to the Earth rather than to a body part. One nautical mile is one minute of latitude, fixed at exactly 1,852 metres, which makes chart work straightforward for anyone navigating by degrees.
How do I write my height in metric?
Convert the whole thing to inches first, then multiply by 2.54. Five foot ten is 70 inches, which is 177.8 cm. Converting the feet and the inches separately is where the arithmetic usually goes wrong.
Meter or metre?
Both name the same unit. "Metre" is the international spelling used by the SI and most English-speaking countries; "meter" is standard in the United States. Either spelling will find this page.
All length units and their conversion factors
| Unit | Symbol | In metres |
|---|---|---|
| Nanometres | nm | 1e-9 |
| Micrometres | µm | 0.000001 |
| Millimetres | mm | 0.001 |
| Centimetres | cm | 0.01 |
| Metres | m | 1 |
| Kilometres | km | 1,000 |
| Inches | in | 0.0254 |
| Feet | ft | 0.3048 |
| Yards | yd | 0.9144 |
| Miles | mi | 1,609.34 |
| Nautical miles | nmi | 1,852 |