Convert cm to inches
One inch is defined as exactly 25.4 millimetres, so one centimetre equals exactly 0.39370078740157 inches. Converting cm to inches is multiplication by 0.39370078740157 (the reciprocal of 2.54). Example: 30 cm × 0.39370078740157 = 11.8110236220472 in.
Type a value and get the result with its full working shown — the coefficient, the multiplication and the rounding you choose.
centimeter → inch
30 × 0.39370078740157 = 11.81102362 in
See the exact formula: 1 cm × 0.39370078740157 → in · Source: BIPM SI Brochure, 9th ed.（1 cm = 0.01 m）.
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cm to inches conversion table
| cm | in |
|---|---|
| 1 cm | 0.3937 in |
| 2 cm | 0.7874 in |
| 3 cm | 1.1811 in |
| 4 cm | 1.5748 in |
| 5 cm | 1.9685 in |
| 6 cm | 2.3622 in |
| 7 cm | 2.7559 in |
| cm | in |
|---|---|
| 8 cm | 3.1496 in |
| 9 cm | 3.5433 in |
| 10 cm | 3.9370 in |
| 25 cm | 9.8425 in |
| 50 cm | 19.6850 in |
| 100 cm | 39.3701 in |
Rounded to 4 decimals · exact values in the calculator above.
The exact formula
The international inch is defined as exactly 25.4 mm (2.54 cm), fixed internationally in 1959. It is used in the US, UK and Canada. Multiply by 0.39370078740157 (cm → in); reverse: multiply by 2.54.
Unit definitions
- centimeter (cm)
- The centimetre is 1/100 of a metre, the SI base unit of length. The metre is defined by fixing the speed of light at exactly 299792458 m/s. Source: BIPM SI Brochure, 9th ed.（1 cm = 0.01 m）.
- inch (in)
- The international inch is defined as exactly 25.4 mm (2.54 cm), fixed internationally in 1959. It is used in the US, UK and Canada. Source: NIST Handbook 44 / NIST SP 811.
Frequently asked questions
How many inches is 1 cm?
One centimetre is exactly 0.39370078740157 inches, because one inch is defined as exactly 2.54 cm.
How many inches is 30 cm?
30 cm = 11.8110236220472 in. Multiply 30 by 0.39370078740157: 30 × 0.39370078740157 = 11.8110236220472 in.
How do I convert cm to inches?
Divide centimetres by 2.54, or multiply by 0.39370078740157. Both give the identical result because 1 in = 25.4 mm exactly.
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