Inches to CM Converter
Exact both ways — the ×2.54 direction for screens, timber, and patterns.
Type in either field — the other updates instantly.
Inches to CM chart
| Inches | Centimeters |
|---|---|
| 0.5 in | 1.27 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 |
| 15 in | 38.1 cm |
| 18 in | 45.72 cm |
| 20 in | 50.8 cm |
| 24 in | 60.96 cm |
| 27 in | 68.58 cm |
| 32 in | 81.28 cm |
| 40 in | 101.6 cm |
| 50 in | 127 cm |
| 65 in | 165.1 cm |
| 100 in | 254 cm |
How this is calculated
cm = inches × 2.54 (exact — the inch is defined as 25.4 mm)
This is the direction for turning US measurements metric: a 27-inch monitor is 68.58 cm wide-diagonal, a 2-inch hem allowance is 5.08 cm. Because the inch is defined as exactly 25.4 mm, multiplying by 2.54 is exact — no approximation involved.
The ×2.54 factor is a definition, not a measurement, fixed by the 1959 international yard-and-pound agreement. Any error you ever see between two converters is display rounding; we round at four decimals, at display time only.
Frequently asked questions
How many cm is 1 inch?
Exactly 2.54 cm — by definition, not approximation. Every inch conversion is a clean multiply: 12 in = 30.48 cm, 36 in = 91.44 cm.
How do I convert screen sizes?
TV and monitor sizes are diagonal inches: a 55-inch TV has a 139.7 cm diagonal. Width and height depend on aspect ratio, so two "55-inch" screens can differ in shape while sharing the diagonal.
What is 5 feet 10 inches in cm?
Convert to total inches first: 5 ft 10 in = 70 in, then × 2.54 = 177.8 cm. For heights, our CM to inches page also splits the answer back into feet and inches.
Is a "metric inch" a thing?
No — since 1959 there is one international inch, defined as exactly 25.4 mm. Older national inches (like the pre-1959 US survey definitions) differed by millionths — irrelevant outside land surveying.