Inches to Centimeters
One inch is exactly 2.54 centimeters. That is not a rounded approximation — it is the legal definition agreed by the English-speaking countries in the 1959 international yard and pound agreement.
Files processed in your browser — never uploaded to our servers1 Inches (in) = 2.54 Centimeters (cm)
1 Inch (in) = 2.54 Centimeter (cm)
Quick Reference
| Inch (in) | Centimeter (cm) |
|---|---|
| 0.1 | 0.254 |
| 0.5 | 1.27 |
| 1 | 2.54 |
| 2 | 5.08 |
| 5 | 12.7 |
| 10 | 25.4 |
| 20 | 50.8 |
| 50 | 127 |
Inches (in) and Centimeters (cm) explained
The inch is the base small-length unit of the imperial and US customary systems. It survives in daily use mainly in the United States, and worldwide in a few stubborn niches: screen diagonals, wheel and tyre rims, plumbing pipe bores, and lumber dimensions. The centimeter is one hundredth of a meter, a decimal subdivision of the SI base unit. It is the unit almost everyone outside the US reaches for when measuring a body, a piece of furniture, or a suitcase. Because the inch is defined in terms of the meter rather than the other way round, every inch-to-centimeter conversion is exact — no rounding error is introduced by the conversion itself.
Formula and worked examples
cm = in × 2.54
Multiply the number of inches by 2.54 to get centimeters. Because the factor is exact, the arithmetic is the only source of error. A 10-inch tablet is 25.4 cm. A 55-inch television has a 139.7 cm diagonal. A person who is 5 feet 10 inches tall is 70 inches, or 177.8 cm. To go back the other way, divide by 2.54 instead of multiplying.
Inches (in) to Centimeters (cm) conversion table
Common Inches (in) values converted to Centimeters (cm). Every figure uses the same conversion factor as the calculator above.
| Inches (in) | Centimeters (cm) |
|---|---|
| 1 | 2.54 |
| 2 | 5.08 |
| 5 | 12.7 |
| 10 | 25.4 |
| 20 | 50.8 |
| 50 | 127 |
| 100 | 254 |
Where you will use this
Buying a screen listed in inches
Televisions and monitors are advertised by diagonal in inches almost everywhere, including in metric countries. Converting to centimeters is how you check whether a 65-inch set (165.1 cm) actually fits the 160 cm alcove you measured with a tape.
Height on a US form
Visa applications, gym sign-ups and medical intake forms in the US ask for height in feet and inches. Convert your centimeter height to total inches first, then divide by 12 for feet and keep the remainder as inches.
Ordering materials from a US supplier
Lumber, drill bits, bolts and pipe fittings from American suppliers are sized in inches and fractions of an inch. A 3/4-inch fitting is 1.905 cm, which is not interchangeable with the 20 mm metric fitting it superficially resembles.
Pro tip
For a fast mental estimate, multiply by 2.5 and add about 1.5%. Twelve inches becomes 30 plus a bit, and the true answer is 30.48 cm. The shortcut is roughly 1.6% low, which is close enough for judging whether furniture will fit but not for anything you intend to cut.