Convert centimetres to inches
1 cm = 0.393701 in
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All unit convertersQuestions
How many inches are in a centimetre?
One centimetre is 0.393700787 inches. To convert any amount, multiply by 0.393700787. Going the other way, one inch is 2.54 centimetres.
What is the formula to convert cm to in?
Multiply the centimetre figure by 0.393700787. So in = cm × 0.393700787. For a quick mental estimate, dividing by about 2.54 gets you close enough for most everyday purposes.
What does a centimetre actually look like?
One centimetre is about the width of an adult fingernail. The centimetre is the everyday metric unit for body measurements and paper sizes, though it is not an SI-preferred prefix step — engineers tend to jump from millimetres to metres.
And what is a inch?
One inch is roughly the width of an adult thumb. The inch has been exactly 25.4 millimetres since 1959. Screen sizes, pipe diameters and tyre rims are still specified in inches almost universally.
Is this conversion exact?
Yes. Since the 1959 international yard and pound agreement, the imperial and metric systems are related by exact definitions rather than measurements — the inch is exactly 25.4 mm and the pound exactly 0.45359237 kg. Everything derived from those, including this conversion, is therefore exact. Round at the end rather than partway through, since rounding cm before converting introduces an error the conversion then multiplies.
About cm to in
How to convert centimetres to inches
Multiply by 0.393700787. One centimetre is 0.393700787 inches, and one inch is 2.54 centimetres.
in = cm × 0.393700787
Worked example
10 cm = 3.937008 in. For a sense of scale, one centimetre is about the width of an adult fingernail, and one inch is roughly the width of an adult thumb.
About the centimetre
The centimetre is the everyday metric unit for body measurements and paper sizes, though it is not an SI-preferred prefix step — engineers tend to jump from millimetres to metres.
About the inch
The inch has been exactly 25.4 millimetres since 1959. Screen sizes, pipe diameters and tyre rims are still specified in inches almost universally.
Quick reference
| centimetres | inches |
|---|---|
| 1 cm | 0.393701 in |
| 2 cm | 0.787402 in |
| 5 cm | 1.9685 in |
| 10 cm | 3.93701 in |
| 25 cm | 9.84252 in |
| 50 cm | 19.685 in |
| 100 cm | 39.3701 in |
| 1000 cm | 393.701 in |
Getting it right
This conversion is exact by definition, so the only limit on accuracy is how many digits you keep. Round at the end rather than partway through — rounding cm to a whole number before converting introduces an error that the conversion then multiplies.
Other length conversions
Convert inches back to centimetres, or pick any other pair with the full unit converter. Related: cm to km, cm to m, cm to mm.