To convert inches to centimeters, multiply by 2.54. One inch is exactly 2.54 cm, so 12 inches (a foot) is 30.48 cm and a 32-inch waist is 81.28 cm.
Inches are still the everyday unit in the United States for screen sizes, clothing, lumber and kids' growth charts. If you're buying from an overseas store, filling in a metric form, or reading a sewing pattern printed in centimeters, this is the conversion you need.
How to use the inches to cm converter
- Type the value in inches into the box. Decimals are fine.
- The result in centimeters updates as you type, along with the working.
- Need the other way? Switch the direction menu, or open the cm to inches converter.
Formula
The factor 2.54 is exact. Since the 1959 international yard and pound agreement, one inch has been defined as exactly 25.4 millimeters, so no rounding is involved in either direction.
Worked example
Convert a 32-inch waist to centimeters.
- Start with 32 in.
- Multiply by 2.54: 32 × 2.54 = 81.28.
- Result: 81.28 cm. European jeans list this as size 81 or 82 on the waist tag.
Same method for a TV: a 65-inch screen measured on the diagonal is 65 × 2.54 = 165.1 cm.
Inches to centimeters chart
Common values, rounded to 4 decimal places.
| Inches (in) | Centimeters (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 |
| 8 in | 20.32 cm |
| 10 in | 25.4 cm |
| 12 in | 30.48 cm |
| 18 in | 45.72 cm |
| 24 in | 60.96 cm |
| 30 in | 76.2 cm |
| 32 in | 81.28 cm |
| 36 in | 91.44 cm |
| 48 in | 121.92 cm |
| 60 in | 152.4 cm |
| 65 in | 165.1 cm |
| 72 in | 182.88 cm |
Where inches show up
- Screens: TVs, monitors and phones are sold by diagonal size in inches almost everywhere, even in metric countries. A 55-inch TV is 139.7 cm corner to corner.
- Clothing: US waist and inseam sizes (32×30) are inches, while European sizes are centimeters.
- Hardware and lumber: nominal "2×4" lumber is actually 1.5 × 3.5 in (3.81 × 8.89 cm).
- Rainfall and snow: US forecasts report precipitation in inches.
Quick mental math
Multiply by 2.5, then add a little bit more (about 1.6%). For 10 inches: 10 × 2.5 = 25, plus 0.4 = 25.4 cm. For rough work, "inches × 2.5" is within 2%.
Related conversions
Going the other way: cm to inches converter. Related pages: feet to inches converter, inches to feet converter, mm to inches converter. For other units in the same family, use the full length converter.
Caveats and assumptions
- Results show up to 10 significant digits; the chart is rounded for reading. Keep full precision for engineering, medical or legal work.
Frequently asked questions
How many centimeters are in an inch?
Exactly 2.54 centimeters. The value is fixed by definition, not measured.
How tall is 5 feet 6 inches in cm?
5 ft 6 in is 66 inches, and 66 × 2.54 = 167.64 cm. The feet to inches converter page helps if you start from feet.
How big is a 55-inch TV in centimeters?
139.7 cm measured diagonally. Width and height depend on the aspect ratio; a 16:9 55-inch screen is about 121.8 × 68.5 cm.
Is 2.54 rounded?
No. The inch was defined as exactly 25.4 mm in 1959, so 2.54 cm is exact.
Sources
- NIST — SI Units: Length (1959 definition of the inch) — 1 in = 25.4 mm exactly
- NIST SP 811 Appendix B.9 — Conversion factors — inch to centimeter
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