Centimetres to inches converter
Type a length in centimetres and see at once how many inches that is. With the option above the field, the tool also converts from inches to centimetres. Handy for screen sizes, clothing, tyres and orders from abroad.
In centimetres or in inches. 1 inch is exactly 2.54 cm.
Fill in the fields; the answer appears here straight away.
How it's worked out
How it works
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Enter the values
Type the numbers or the formula. Decimals may use a point or a comma. No idea? Click Fill in an example.
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Instant answer
The answer appears as you type, with the most important intermediate values.
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See the working
Under "How it's worked out" you see the steps, handy for checking your own calculation.
The formula
One inch is exactly 2.54 centimetres. So:
- cm to inches: divide by 2.54
- inches to cm: multiply by 2.54
180 cm is 180 ÷ 2.54 = 70.87 inches. A 55-inch television measures 55 × 2.54 = 139.7 cm across the diagonal.
Conversion table
| cm | in |
|---|---|
| 1 cm | 0.39 in |
| 2.5 cm | 0.98 in |
| 5 cm | 1.97 in |
| 10 cm | 3.94 in |
| 15 cm | 5.91 in |
| 20 cm | 7.87 in |
| 30 cm | 11.81 in |
| 50 cm | 19.69 in |
| 100 cm | 39.37 in |
| 180 cm | 70.87 in |
A rule of thumb
2.5 cm is about 1 inch. Twelve inches (1 foot) is 30.48 cm.
Paper sizes
| Paper | Centimetres | Inches |
|---|---|---|
| A4 | 21 × 29.7 | 8.27 × 11.69 |
| US Letter | 21.59 × 27.94 | 8.5 × 11 |
US Letter is a little wider and shorter than A4, which is why a document sometimes shifts when printed on the other format.
Clothing and sizes
Waist and inseam in the US are in inches: a waist of 32 inches is 81.3 cm. Shoe boxes and bicycle frames use inches too. When you order from abroad, convert the measurements for the size chart before you decide.
Screens
A diagonal of 55 inches is 139.7 cm and one of 32 inches is 81.3 cm. Compare it with the exact space on a shelf using the factor 2.54. For a person's height see the metres to feet converter, and for floor areas the square metres to square feet converter.
Frequently asked questions
Why is an inch exactly 2.54 cm?
In 1959 the United States and the Commonwealth countries agreed on an international inch defined as exactly 25.4 millimetres. Before that, small national differences existed.
How do I convert inch fractions like 3/8 inch?
Convert the fraction to a decimal first, 3 ÷ 8 = 0.375 in, and multiply by 2.54: that is 0.9525 cm, or 9.525 mm. The calculator accepts 3/8 as input.
How many centimetres is a foot?
30.48 cm, because a foot is 12 inches. For a body height or a room, use the [metres to feet converter](/en/math/meters-to-feet-converter).
Is the diagonal of a screen measured in inches?
Yes, corner to corner. A 27-inch monitor has a 68.6 cm diagonal, and a 6.1-inch phone is 15.5 cm. The width is smaller, depending on the screen shape.