Centimeters to Inches
A centimeter is a little under half an inch. Divide by 2.54 to convert — type any value and read the result, in either direction.
Your numbers
Result
- Unit
- inches
| Centimeters | Inches |
|---|---|
| 1 | 0.39 |
| 5 | 1.97 |
| 10 | 3.94 |
| 20 | 7.87 |
| 30 | 11.81 |
| 50 | 19.69 |
| 100 | 39.37 |
How to convert cm to inches
Divide the centimeters by 2.54: 30 cm ÷ 2.54 ≈ 11.81 in. To reverse it, multiply by 2.54. Because 1 inch is defined as exactly 2.54 cm, the conversion is exact in both directions — only your rounding introduces error.
A mental shortcut
Need a rough figure without a calculator? Divide by 2.5 and you are within 2% — 100 cm ÷ 2.5 = 40 in, against a true 39.37 in. Useful for a quick sanity check, not for cutting material.
Reading the result on a ruler
Imperial rulers rarely show decimals. To turn 11.81 in into tape-measure language, keep the whole inches and multiply the decimal by 16: 0.81 × 16 ≈ 13, so 30 cm is about 11 13/16 in. The nearest eighth (11 7/8 in) is close enough for most jobs.
Frequently asked questions
Sources
- International yard and pound agreement (1959) — 1 inch = 2.54 cm exactly
- NIST — Office of Weights and Measures
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