1 inch = 2.54 centimetres
Since the 1959 international yard and pound agreement, the inch has been defined as exactly 25.4 millimetres — which makes every imperial length an exact multiple of a metric one. That exactness is why the results below carry to twelve decimal places without approximation. The set spans the nanometre used in semiconductor work up to the furlong still used in horse racing.
Formula centimetres = inches × 2.54
| Inch | Centimetre |
|---|---|
| 1 in | 2.54 cm |
| 2 in | 5.08 cm |
| 3 in | 7.62 cm |
| 5 in | 12.7 cm |
| 10 in | 25.4 cm |
| 25 in | 63.5 cm |
| 50 in | 127 cm |
| 100 in | 254 cm |
| 250 in | 635 cm |
| 500 in | 1270 cm |
| 1000 in | 2540 cm |
The metre is the SI base unit of length and is now defined from the speed of light. Everyday metric lengths are built on it: a centimetre is one hundredth of a metre and a millimetre is one thousandth. The imperial and US customary units are defined from the metre too. Since the 1959 international agreement, one inch is exactly 25.4 mm, one foot is exactly 0.3048 m and one yard is exactly 0.9144 m.
Two anchors cover most conversions. An inch is 2.54 cm, so a 10 inch screen is about 25.4 cm. A foot is 30.48 cm, so a person 5 feet 10 inches tall is 177.8 cm. For rough work, 30 cm is a foot and a metre is a bit over three feet (3.28). To convert metres to feet, multiply by 3.28084. To go the other way, divide.
The older US survey foot, used in land surveying, differs from the international foot by about two parts per million and was retired in 2023, so the international foot is the one used here. For longer distances such as road trips, see the distance converter.
Related guides: Imperial vs metric: differences and quick conversion tricks