Inches to CM Converter
Type inches to get centimeters. One inch is exactly 2.54 cm, so the answer is exact, not an estimate.
12 in =
30.48cm
12 inches is 30.48 centimeters.
- 1 in
- 2.54 cm
- 1 cm
- 0.3937 in
How this works: Method, 4 sources, Checked against 1 worked example,
How this works
Method
Multiply the inches by 2.54. The international inch is defined as exactly 25.4 millimeters, so the product is exact; only rounding it for display loses anything. Full method
Sources
How it’s tested
One worked example for this page is checked by automated tests before every release: given the inputs, the tool must show the expected answer.
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Changes
- Ask understands “5 ft 9 in to cm” and “2 cups of flour in grams” and answers at once, and a decimal comma (“2,5”) reads as 2.5.
- First published: 89 everyday units across ten quantities, with 58 pages for common pairs such as cm to inches and Celsius to Fahrenheit.
How to convert inches to cm
Multiply the inches by 2.54. The international inch is defined as exactly 25.4 millimeters, so the product is exact; only rounding it for display loses anything.
A 15.6-inch laptop screen measures 15.6 × 2.54 = 39.624 cm along its diagonal. Jeans with a 32-inch waist are 32 × 2.54 = 81.28 cm round, and a 6-inch sandwich is 15.24 cm long.
When the length is given in feet and inches, turn it all into inches before multiplying: 5 ft 3 in is 63 inches, and 63 × 2.54 = 160.02 cm. The feet and inches page takes both numbers directly.
centimeters = inches × 2.54
- Before 1959 the US inch was based on 39.37 inches to the meter, making it 2.540005 cm. That older inch lived on in the US survey foot until it was retired at the end of 2022. Source: NIST, The U.S. survey foot (deprecated from 1 January 2023).
How to estimate inches to cm in your head
Multiply by 2.5: double the inches, then add half of the original number. For 12 inches that is 24 + 6 = 30 cm, against a true 30.48. Using 2.5 instead of 2.54 comes out about 1.6% short, so add roughly 1 cm for every 25 inches.
Handy anchors: 4 inches is a hair over 10 cm (10.16), a foot is 30.5 cm, and 39 inches is just under a meter (99.06 cm). Scale up or down from whichever anchor is nearest.
Inches to centimeters chart
Common inch measurements, from half an inch to a 65-inch TV, in centimeters.
| Inches (in) | Centimeters (cm) | Example |
|---|---|---|
| 0.5 | 1.27 | |
| 1 | 2.54 | |
| 2 | 5.08 | |
| 3 | 7.62 | |
| 4 | 10.16 | |
| 5 | 12.7 | |
| 6 | 15.24 | |
| 8 | 20.32 | |
| 10 | 25.4 | |
| 11 | 27.94 |
Show all 26 rowsShow fewer
| 12 | 30.48 | one foot |
| 13 | 33.02 | |
| 14 | 35.56 | |
| 15.6 | 39.624 | a common laptop screen |
| 17 | 43.18 | |
| 18 | 45.72 | |
| 20 | 50.8 | |
| 24 | 60.96 | |
| 27 | 68.58 | a desktop monitor |
| 32 | 81.28 | a 32-inch waist |
| 36 | 91.44 | one yard |
| 40 | 101.6 | |
| 43 | 109.22 | |
| 50 | 127 | |
| 55 | 139.7 | a 55-inch TV |
| 65 | 165.1 |
Frequently Asked Questions
How many cm is 5 inches?
5 inches is exactly 12.7 cm (5 × 2.54), half of the 25.4 cm in ten inches.
What is 36 inches in cm?
36 inches is 91.44 cm, which is exactly one yard. It is about 8.6 cm short of a meter.
Why do some charts say an inch is 2.5 cm?
2.5 is a rounded figure that is handy for quick sums. It undercounts by 0.04 cm per inch, so over 40 inches the error reaches 1.6 cm, too much for sewing or fitting furniture. Use 2.54 when it matters.
How do I convert a chest or waist size from inches to cm?
Multiply the measurement by 2.54. A 34-inch chest is 86.36 cm and a 30-inch inseam is 76.2 cm.