How it works
The inch is defined as exactly 2.54 centimetres (since 1959), so this conversion has no rounding at all in the inches-to-cm direction. Inches are still everywhere even in metric countries: TV and phone screens, laptop sizes, tyre and wheel rims, pipe fittings and jeans waist sizes are all quoted in inches.
The formula
inches = cm ÷ 2.54 cm = inches × 2.54Worked example. A 55-inch TV has a diagonal of 55 × 2.54 = 139.7 cm. A 6.7-inch phone screen is 17.02 cm. A height of 180 cm is 180 ÷ 2.54 = 70.87 in, which is 5 ft 10.87 in.
Quick reference table
| Centimetres | Inches | Inches | Centimetres |
|---|---|---|---|
| 1 cm | 0.3937 in | 1 in | 2.54 cm |
| 2 cm | 0.7874 in | 2 in | 5.08 cm |
| 5 cm | 1.9685 in | 5 in | 12.7 cm |
| 10 cm | 3.937 in | 10 in | 25.4 cm |
| 15 cm | 5.9055 in | 15 in | 38.1 cm |
| 20 cm | 7.874 in | 20 in | 50.8 cm |
| 30 cm | 11.811 in | 30 in | 76.2 cm |
| 50 cm | 19.685 in | 50 in | 127 cm |
| 75 cm | 29.5276 in | 75 in | 190.5 cm |
| 100 cm | 39.3701 in | 100 in | 254 cm |
| 150 cm | 59.0551 in | 150 in | 381 cm |
| 180 cm | 70.8661 in | 180 in | 457.2 cm |
Screen sizes are diagonals
A “65-inch” TV measures 65 in (165.1 cm) from one corner to the opposite corner, not across the width. For a 16:9 screen the width is about 0.87 × the diagonal — roughly 144 cm for a 65-inch TV.
Feet and inches
12 inches make a foot (30.48 cm). To write a height in feet and inches, divide the inches by 12: 70.87 in = 5 ft and 10.87 in. The feet to metres converter handles feet directly.
Need millimetres, yards or miles? Use the full unit converter.