How centimetres and inches are converted
The exact conversion factor is 2.54 centimetres per inch. Only the displayed results are rounded.
inches = centimetres ÷ 2.54, and centimetres = inches × 2.54
- Divide centimetres by 2.54 to get inches.
- To convert inches back to centimetres, multiply by 2.54. Multiply centimetres by 10 for millimetres.
- For a ruler fraction, round the inches to the nearest 1/16 and reduce the fraction. 10 cm is about 3 15/16 in.
- For lengths of at least 12 inches, take out whole feet and show the remaining inches to 2 decimal places.
Worked example: 10 cm ÷ 2.54 = 3.937 in, or about 3 15/16 in on a ruler. The same length is 100 mm.
Common centimetre lengths converted
| Centimetres | Inches |
|---|---|
| 1 cm | 0.3937 in |
| 2 cm | 0.7874 in |
| 5 cm | 1.9685 in |
| 10 cm | 3.937 in |
| 15 cm | 5.9055 in |
| 20 cm | 7.874 in |
| 25 cm | 9.8425 in |
| 30 cm | 11.811 in |
| 50 cm | 19.685 in |
| 100 cm | 39.3701 in |
| 150 cm | 59.0551 in |
| 160 cm | 62.9921 in |
| 170 cm | 66.9291 in |
| 180 cm | 70.8661 in |
Swipe the table sideways to see the rest.
Inches are rounded to 4 decimal places. One inch is exactly 2.54 cm.
Things to consider
- Use the decimal result for calculations, rather than the rounded ruler fraction.
- A sixteenth of an inch is 1.5875 mm. Rounding to the nearest mark can change a length by up to 0.79375 mm.
- 170 cm is 5 ft 6.93 in here. Rounded to a whole inch, that is 5 ft 7 in.
- Convert each dimension separately before comparing sizes. This converter handles length, not area or volume.
Frequently asked questions
How many centimetres are in an inch?
Exactly 2.54 cm. That is also exactly 25.4 mm.
How do I convert centimetres to inches?
Divide the centimetres by 2.54. For example, 10 ÷ 2.54 = 3.937 in when rounded to 4 decimal places.
How tall is 170 cm in feet and inches?
170 cm is 66.9291 inches, or 5 ft 6.93 in with the remaining inches rounded to 2 decimal places. To the nearest whole inch it is 5 ft 7 in. Use the Feet to Inches Converter for a height already written in feet and inches.
How do I read a ruler fraction?
On a ruler divided into sixteenths, count the small marks after a whole inch. 3 15/16 in means 3 whole inches plus 15 of those marks. Fractions are reduced, so 8/16 is shown as 1/2 and 4/16 as 1/4. The fraction here is an approximation to the nearest mark.
How do I convert inches to centimetres?
Multiply inches by 2.54. One inch is 2.54 cm and 12 inches is 30.48 cm. Choose Inches to cm to see centimetres and millimetres.
Results are estimates for general information only, not financial, medical or professional advice.