Inches to Centimeters (in to cm)
Multiply inches by 2.54 to get centimeters. That factor is exact, not rounded, so 12 in is exactly 30.48 cm and 36 in (one yard) is 91.44 cm. Change either box and the other one updates.
Convert inches to cm
Result
inches to cm
12 in = 30.48 cm
1 in = 2.54 cm · 1 cm = 0.393701 in
Show the mathHow it was calculated
cm = in × 2.54
Uses exact legal definitions; results are rounded to 6 significant figures for display.
How to convert inches to cm
cm = in × 2.54
One inch is exactly 2.54 centimeters, so multiply by 2.54.
Worked example: converting 12 in:
- cm = in × 2.54
- 12 in × 2.54 = 30.48 cm
Inches to cm conversion table
Common values, each computed with the exact formula and rounded to 6 significant figures.
| Inches (in) | Centimeters (cm) |
|---|---|
| 0.25 in | 0.635 cm |
| 0.5 in | 1.27 cm |
| 0.75 in | 1.905 cm |
| 1 in | 2.54 cm |
| 2 in | 5.08 cm |
| 3 in | 7.62 cm |
| 4 in | 10.16 cm |
| 5 in | 12.7 cm |
| 6 in | 15.24 cm |
| 7 in | 17.78 cm |
| 8 in | 20.32 cm |
| 9 in | 22.86 cm |
| 10 in | 25.4 cm |
| 11 in | 27.94 cm |
| 12 in | 30.48 cm |
| 14 in | 35.56 cm |
| 16 in | 40.64 cm |
| 18 in | 45.72 cm |
| 20 in | 50.8 cm |
| 24 in | 60.96 cm |
| 27 in | 68.58 cm |
| 30 in | 76.2 cm |
| 32 in | 81.28 cm |
| 34 in | 86.36 cm |
| 36 in | 91.44 cm |
| 40 in | 101.6 cm |
| 43 in | 109.22 cm |
| 48 in | 121.92 cm |
| 50 in | 127 cm |
| 55 in | 139.7 cm |
| 60 in | 152.4 cm |
| 65 in | 165.1 cm |
| 70 in | 177.8 cm |
| 72 in | 182.88 cm |
| 75 in | 190.5 cm |
| 85 in | 215.9 cm |
Quick reference: everyday inches in centimeters
Quarter inch
0.25 in = 0.635 cm
One foot
12 in = 30.48 cm
Common 27-inch monitor (diagonal)
27 in = 68.58 cm
One yard
36 in = 91.44 cm
Common 55-inch TV (diagonal)
55 in = 139.7 cm
Height of 5 ft 10 in
70 in = 177.8 cm
TVs, monitors and wheel sizes
Screen sizes are diagonal measurements in inches. A 55-inch TV is 139.7 cm corner to corner, and a 27-inch monitor is 68.6 cm. The width depends on the aspect ratio. For a 16:9 screen it's about 87% of the diagonal, so a 55-inch set is roughly 121.8 cm (48 in) wide before the bezel.
Bicycle wheel sizes such as 26, 27.5 and 29 inches are names rather than precise measurements. The rim that actually fits a tire is specified in millimeters under the ISO (ETRTO) system, and a 29-inch mountain bike rim has the same 622 mm bead seat as a 700c road rim. Converting the nominal inch size won't tell you which tire fits.
Nominal lumber and fractional inches
North American dimensional lumber is named by its rough-sawn size, not its finished size. A 2×4 is actually 1.5 × 3.5 in, or 3.81 × 8.89 cm. Convert the actual size, not the name, when you compare it with metric timber or check that it fits a bracket.
Tape measures in the US mark fractions of an inch. To convert one, change it to a decimal first: 3/8 in = 0.375 in = 0.9525 cm. If you are adding several fractional measurements before converting, our fraction calculator keeps the arithmetic exact. Area jobs such as flooring are easier with the flooring calculator, which handles both unit systems.
Frequently asked questions
How many centimeters are in a foot?
Exactly 30.48 cm, because a foot is 12 inches and each inch is 2.54 cm. A common mistake is to use 30 cm per foot, which makes a 10-foot wall 300 cm instead of 304.8 cm. That's almost 5 cm short, which is enough to matter when ordering trim or curtain rails.
How do I convert my height in feet and inches to cm?
Turn the height into total inches first (feet × 12 plus the extra inches), then multiply by 2.54. For 5 ft 10 in: 5 × 12 + 10 = 70 in, and 70 × 2.54 = 177.8 cm. Many forms want a whole number, so round only the final figure (178 cm), never the inches.
Are inches the same in the US and the UK?
Yes. Since the 1959 international yard and pound agreement, the inch has been exactly 2.54 cm in the US, UK, Canada, Australia and the other countries that use it. Unlike gallons or fluid ounces, there's no separate 'imperial inch' to worry about, so one conversion factor works everywhere.