Unit converter
Centimeters to Inches Converter
Convert centimetres to inches instantly. One inch is defined as exactly 2.54 centimetres, a value fixed by international agreement in 1959, so every centimetres to inches conversion is exact rather than approximate. Type any length in centimetres and this tool shows the equivalent in inches, with a quick reference table for the values people look up most. It is handy for reading a tape measure marked in centimetres against an American ruler, sizing a TV or monitor, checking clothing and shoe measurements, or following a craft pattern written in the other system.
1 centimeter = 0.393701 inches
Common centimeters to inches values
| Centimeters | Inches |
|---|---|
| 1 cm | 0.393701 in |
| 2 cm | 0.787402 in |
| 5 cm | 1.9685 in |
| 10 cm | 3.937 in |
| 20 cm | 7.874 in |
| 50 cm | 19.685 in |
| 100 cm | 39.3701 in |
How to convert
- Take the length in centimetres that you want to convert.
- Divide it by 2.54, because one inch equals exactly 2.54 centimetres.
- The answer is the same length expressed in inches.
- To go the other way, multiply a figure in inches by 2.54 to get centimetres.
- For a rough mental estimate, divide by 2.5: 10 cm is close to 4 inches, and 30 cm is close to 12 inches (one foot).
inches = centimetres / 2.54
Because one inch is exactly 2.54 centimetres, dividing a length in centimetres by 2.54 gives the same length in inches. Multiplying inches by 2.54 reverses it. The factor never changes, so the conversion is a single fixed division.
- cm
- the length in centimetres you start with
- 2.54
- centimetres in one inch, by definition
Worked example
A 70 cm cabinet shelf is 70 divided by 2.54, which is about 27.56 inches. A 165 cm height works out at roughly 64.96 inches, or about 5 feet 5 inches once you split the inches into feet.
Key facts
- One inch is exactly 2.54 cm; one centimetre is about 0.3937 inches.
- A4 paper is 21 cm wide, which is about 8.27 inches.
- A 165 cm person is roughly 5 feet 5 inches tall.
- Screen sizes are quoted in diagonal inches: a 140 cm diagonal is about 55 inches.
Tips
- For a fast estimate, halve the centimetres and take a bit off: 20 cm is close to 8 inches.
- When buying online from a US site, convert the inch sizes to centimetres against a tape measure you already own.
- Keep the full precision until the final step, then round, so small errors do not build up.
Frequently asked questions
How many inches is 1 cm?+
One centimetre is 0.393701 inches, a little under four tenths of an inch. It is the reciprocal of 2.54.
Is the conversion exact?+
Yes. Since 1959 the inch has been defined as exactly 2.54 cm, so converting between the two involves no rounding beyond the decimal places you choose to show.
How do I convert cm to feet and inches?+
Divide the centimetres by 2.54 to get total inches, then divide those inches by 12. The whole number is the feet and the remainder is the leftover inches.
Why do some rulers show both?+
Most of the world measures in centimetres while the United States and a few others use inches, so dual-scale rulers and tape measures save converting by hand.
Things to watch
- Rounding inches to whole numbers can lose up to half a centimetre, which matters for a tight fit.
Sources
Last updated: 2026-01-01
Conversions use internationally defined factors. Provided for general use; verify critical measurements independently.