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Centimetres to Inches Converter

Convert centimetres to inches in the browser. Fractions welcome, up to ten decimal places, and the factor is exact.

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Convert a length

Conversion values

Inchesin

11.81
Units and precision
1 cm = 0.393701 in

How it works

  1. 01

    Type a length in centimetres

    Plain numbers, decimals or fractions. The answer updates as you type, with no button to press.

  2. 02

    Read the inches

    The swap button reverses the conversion and carries the answer across, so you can check it both ways.

  3. 03

    Choose the precision

    Up to ten decimal places. Two is enough for anything you can measure by hand.

Conversion table

Common centimetre measurements and their inch equivalents
CentimetresInchesCentimetresInches
10.39259.84
20.793011.81
51.975019.69
103.9410039.37
155.9115059.06
207.8718070.87

Where the number comes from

Only one direction of this conversion is a clean number. The inch was defined as exactly 25.4 millimetres by international agreement in 1959, so an inch is exactly 2.54 cm. Turn that around and you get 0.3937007874 inches per centimetre, a figure that never ends.

So the accurate way is to divide by 2.54, instead of multiplying by a rounded 0.3937. This page divides, and it rounds only when it prints the answer at the decimal places you chose.

For a rough check in your head, divide by two and a half and take a little off. Thirty centimetres is about twelve inches, and the exact answer is 11.81. That is close enough for a shelf or a suitcase.

Factor
1 cm = 0.393701 in, or 1 in = 2.54 cm
Quick rule
Divide by 2.5, then take a little off.
Rounding
Up to 10 decimal places, your choice.
Other units
The From and To lists cover mm, m, ft, yd and more.

Frequently asked questions

How many inches are in a centimetre?
About 0.393701. The clean number runs the other way, because an inch is exactly 2.54 cm. So going from centimetres to inches means dividing by 2.54, and the answer rarely lands on a round figure.
Is there a rule I can do in my head?
Divide by two and a half, then take a little off. For 30 cm that gives about 12 inches, and the exact answer is 11.81. That is good enough to check a screen size or a shelf.
Why is the factor exact one way but not the other?
Because the inch is the one that was defined. Since 1959 it has been exactly 25.4 mm by agreement. Turning that around gives 0.3937007874 and so on, which never ends.
Can I get feet and inches instead?
Set the To field to Foot and the answer comes with a feet and inches line under it. For a height, use the cm to feet page, which is built for it.
Does it handle fractions like 3 1/2?
Yes. Fractions and mixed numbers both work. So 1/8, 3 1/2 and -2 1/4 all convert as you would read them off a tape.
Is there a limit on conversions?
No. Conversions run in your browser and have no daily or account limit.
Does this work without an internet connection?
Yes. Once the page has loaded, the sum runs on your device without sending the number anywhere.

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