📏 Length & height
cm to inches Converter
Enter centimetres, choose inches and press Convert. One inch is exactly 2.54 cm, so 180 cm is 70.87 in.
About the cm to inches Converter
Since 1959 the inch has been defined as exactly 25.4 mm, which makes 1 cm equal to 1 ÷ 2.54 = 0.3937007874 in. That exactness is useful because the common shortcut of dividing by 2.5 drifts by more than 1.5% — a whole inch over a two-metre span.
Screens, paper and clothing sizes are quoted in inches in the US and UK, while everything in metric countries is in centimetres. Height is the most common query: 170 cm is 5 ft 6.9 in, and 180 cm is 5 ft 10.9 in.
How the calculation works
- Inches = centimetres ÷ 2.54
- Centimetres = inches × 2.54
- 1 cm = 0.3937007874 in · 1 in = 2.54 cm
Reference values
| Centimetres | Inches | Nearest common fraction |
|---|---|---|
| 1 cm | 0.3937 in | 3/8 in |
| 2.54 cm | 1.0000 in | 1 in |
| 10 cm | 3.9370 in | 3 15/16 in |
| 30 cm | 11.811 in | 11 13/16 in |
| 50 cm | 19.685 in | 19 11/16 in |
| 100 cm | 39.370 in | 39 3/8 in |
| 170 cm | 66.929 in | 5 ft 6.9 in |
| 180 cm | 70.866 in | 5 ft 10.9 in |
Worked examples
- 165 cm ÷ 2.54 = 64.96 in, or 5 ft 4.96 in.
- 175 cm is 68.90 in, and 182 cm is 71.65 in.
- A 30 cm ruler is 11.81 in, which is why it is not interchangeable with a 12 in ruler.
Checking the answer by hand
Divide by 2.5 for a rough figure and expect it to be about 1.6% high: 180 cm ÷ 2.5 gives 72 in where the exact answer is 70.87 in. If your estimate is below the converter's answer, you divided by too large a number.
Common mistakes
- Using 2.5 as the factor: it is 1.6% out, which is a full inch over a two-metre span.
- Converting a diagonal measurement as if it were width — a 55 in television is 121 cm wide, not 140 cm.
- Rounding to whole inches before converting a fraction, which loses up to 1.27 cm.
A last check on the numbers: 37 Centimetre works out to 14.57 Inch, and reversing that with the same factor brings you back to 37 Centimetre. Because Centimetre to Inch is a single multiplication, any tool that gives a different figure for the same input is rounding somewhere in the middle rather than only at the end.