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CM to Inches Converter

Convert centimeters to inches instantly, with a reference table for the sizes you look up most.

CM to Inches Converter

1 cm = 0.3937 in

Multiply centimeters by 0.39370079 to get inches.

Centimeters to inches reference table

The conversions people look up most often, rounded to 4 decimal places.

Common centimeters to inches conversions
Centimeter (cm)Inch (in)
1 cm0.3937 in
2 cm0.7874 in
5 cm1.9685 in
10 cm3.937 in
15 cm5.9055 in
20 cm7.874 in
25 cm9.8425 in
30 cm11.811 in
50 cm19.685 in
100 cm39.3701 in
150 cm59.0551 in
180 cm70.8661 in
200 cm78.7402 in

How the cm to inches converter calculation works

One inch is defined as exactly 2.54 centimeters, so converting between the two is a single division:

inches = centimeters ÷ 2.54

That definition is not an approximation. Since the international yard and pound agreement of 1959, the inch has been legally defined in metric terms, which is why every cm-to-inch conversion you will ever do resolves to the same exact factor.

For a worked example, take a 30 cm ruler. Divide 30 by 2.54 and you get 11.811 inches — just under the 12-inch foot ruler it is designed to replace. A 180 cm person is 180 ÷ 2.54 = 70.87 inches, or 5 feet 10.9 inches once you divide by 12 and convert the remainder.

Two shortcuts worth knowing:

  • For rough mental math, divide by 2.5. A centimeter is a bit under four tenths of an inch, so halving and halving again gets you within about 2%. 100 cm ÷ 2.5 = 40, against a true answer of 39.37.
  • Watch the rounding on small values. At 1-2 cm the difference between 0.39 and 0.394 inches matters for machining or fabric, so use the full four decimal places the converter shows rather than the rounded table figure.

Going the other way is just as simple — multiply inches by 2.54 to get centimeters. The converter above switches direction with one tap.

Frequently asked questions

How do I convert centimeters to inches?

Multiply the number of centimeters by 0.393700787 to get inches.

How many inches are in 15 cm?

15 cm equals 5.9055 in. The reference table on this page lists the other values people look up most often.

How do I convert inches back to centimeters?

Divide the number of inches by 0.393700787, or use the swap control on the converter above.

Is this conversion exact?

Yes. The factor is fixed by international definition rather than measured, so the conversion is exact - only the displayed rounding limits precision.

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