Inches to Centimeters Converter

About the in to cm calculation

One inch is exactly 2.54 centimeters, so converting between them is a single multiplication. Enter any value above and the result updates as you type. Still standard for screen sizes, pipe diameters and tyre rims worldwide. How height and clothing sizes are quoted almost everywhere outside the US.

Formula

cm = in × 2.54

1 in = 2.54 cm
1 cm = 0.393701 in

Worked example

To convert 12 in, multiply by 2.54: 12 × 2.54 = 30.48 cm.

Frequently asked questions

How many centimeters are in a inch?

There are 2.54 centimeters in one inch. To convert any amount, multiply the number of inches by 2.54.

How do I convert centimeters back to inches?

Divide instead of multiplying, or equivalently multiply by 0.393701. One centimeter is 0.393701 inches.

Is this conversion exact?

Yes. Since the international agreement of 1959, the relationship between inches and centimeters is defined exactly rather than measured, so the only rounding here is in how many decimal places we show.

Where is each of these units used?

Inches: still standard for screen sizes, pipe diameters and tyre rims worldwide. Centimeters: how height and clothing sizes are quoted almost everywhere outside the US.

Sources

• NIST Special Publication 811 — Guide for the Use of the International System of Units