How this calculator works
Both units are defined in metres: 1 cm is 0.01 m and 1 in is exactly 0.0254 m. Converting centimetres to inches therefore divides by the exact factor 2.54. Repeating quotients are rounded to 6 significant digits for the readout.
Formula
inches = centimetres ÷ 2.54, because 1 in = 2.54 cm exactly (0.0254 m ÷ 0.01 m).
Worked example
30 cm to inches: 30 ÷ 2.54 = 11.811 in.
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Frequently asked questions
Is the 2.54 factor an approximation?
No. Since the 1959 international yard and pound agreement, the inch is legally defined as exactly 25.4 mm.
How do I convert inches back to centimetres?
Multiply by 2.54, or switch the units on this page; the answer updates as you type.
How do I convert a height given in feet and inches?
Convert it to inches first by multiplying the feet by 12 and adding the inches, then divide by 2.54. The centimetres to feet and inches page gives a split readout.