Conversion guide
Centimeters to inches: formula, table, and examples
Use this reference when a metric measurement in centimeters must be read in inches. The calculator above gives the result immediately; the guide below explains the exact relationship and shows how to check it by hand.
Formulas in both directions
in = cm ÷ 2.54cm = in × 2.54Because the international inch is defined as exactly 2.54 cm, dividing by 2.54 is an exact conversion operation. Only the displayed decimal result is rounded.
Common conversion values
| centimeter (cm) | inch (in) |
|---|---|
| 1 cm | 0.3937007874 in |
| 2 cm | 0.7874015748 in |
| 5 cm | 1.968503937 in |
| 10 cm | 3.937007874 in |
| 20 cm | 7.874015748 in |
| 30 cm | 11.81102362 in |
| 50 cm | 19.68503937 in |
| 75 cm | 29.52755906 in |
| 100 cm | 39.37007874 in |
| 150 cm | 59.05511811 in |
| 180 cm | 70.86614173 in |
| 200 cm | 78.74015748 in |
Worked real-world examples
Example 1
A picture frame is 30 cm wide. Convert its width before ordering inch-based mounting hardware.
30 ÷ 2.54 = 11.8110236230 cm = 11.81102362 inExample 2
A cabinet has a stated height of 180 cm. Convert it to inches to compare with an imperial specification sheet.
180 ÷ 2.54 = 70.86614173180 cm = 70.86614173 inWhat the units mean
centimeter (cm)
A centimeter is one hundredth of a meter. It is an SI-derived metric unit used for everyday dimensions that are too small to describe conveniently in meters.
inch (in)
An inch is a customary length unit defined internationally as exactly 25.4 millimeters, or 2.54 centimeters.
Where these units are used
Centimeters are standard in most countries and in scientific or technical work. Inches remain common for screen sizes, hardware, clothing measurements, and construction in the United States, and in selected uses in Canada and the United Kingdom.
Important distinctions
This page uses the international inch. Historical local inches are not used. A diagonal screen size in inches is not the same as its width, so compare like-for-like dimensions.
Accuracy and rounding
Keep at least four decimal places during intermediate work. Two decimals are normally enough for furniture or screen dimensions; machining and engineering may require the tolerance specified on the drawing.
Frequently asked questions
How many inches are in 1 centimeter?
One centimeter is approximately 0.3937007874 inches. That decimal comes from the exact relationship 1 inch = 2.54 centimeters.
Can I multiply centimeters by 0.4?
Multiplying by 0.4 is a quick estimate, but it is about 1.6% high. Use division by 2.54 when fit or accuracy matters.
Why is the answer sometimes a long decimal?
The reciprocal of 2.54 does not terminate in base ten, so most centimeter values produce repeating decimal inches.
Does this converter use US inches or UK inches?
It uses the international inch adopted for modern US and UK measurement: exactly 2.54 cm.