How do you convert inches to centimeters?
Multiply the number of inches by 2.54. This factor isn't an approximation but a definition: since 1959 the international inch has been defined as exactly 2.54 cm.
inches = centimeters ÷ 2.54
Screen diagonals and common sizes
| 1 in | 2.54 cm |
| 3 in | 7.62 cm |
| 6 in (smartphone) | 15.24 cm |
| 10 in (tablet) | 25.40 cm |
| 13 in (laptop) | 33.02 cm |
| 15 in (laptop) | 38.10 cm |
| 20 in | 50.80 cm |
| 24 in (monitor) | 60.96 cm |
| 32 in (TV) | 81.28 cm |
| 40 in | 101.60 cm |
| 55 in (TV) | 139.70 cm |
Show every value
- 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
- 13 in = 33.02 cm
- 14 in = 35.56 cm
- 15 in = 38.1 cm
- 16 in = 40.64 cm
- 17 in = 43.18 cm
- 18 in = 45.72 cm
- 19 in = 48.26 cm
- 20 in = 50.8 cm
- 21 in = 53.34 cm
- 22 in = 55.88 cm
- 23 in = 58.42 cm
- 24 in = 60.96 cm
- 25 in = 63.5 cm
- 26 in = 66.04 cm
- 27 in = 68.58 cm
- 28 in = 71.12 cm
- 29 in = 73.66 cm
- 30 in = 76.2 cm
- 31 in = 78.74 cm
- 32 in = 81.28 cm
- 33 in = 83.82 cm
- 34 in = 86.36 cm
- 35 in = 88.9 cm
- 36 in = 91.44 cm
- 37 in = 93.98 cm
- 38 in = 96.52 cm
- 39 in = 99.06 cm
- 40 in = 101.6 cm
- 41 in = 104.14 cm
- 42 in = 106.68 cm
- 43 in = 109.22 cm
- 44 in = 111.76 cm
- 45 in = 114.3 cm
- 46 in = 116.84 cm
- 47 in = 119.38 cm
- 48 in = 121.92 cm
- 49 in = 124.46 cm
- 50 in = 127 cm
- 51 in = 129.54 cm
- 52 in = 132.08 cm
- 53 in = 134.62 cm
- 54 in = 137.16 cm
- 55 in = 139.7 cm
- 56 in = 142.24 cm
- 57 in = 144.78 cm
- 58 in = 147.32 cm
- 59 in = 149.86 cm
- 60 in = 152.4 cm
- 61 in = 154.94 cm
- 62 in = 157.48 cm
- 63 in = 160.02 cm
- 64 in = 162.56 cm
- 65 in = 165.1 cm
- 66 in = 167.64 cm
- 67 in = 170.18 cm
- 68 in = 172.72 cm
- 69 in = 175.26 cm
- 70 in = 177.8 cm
- 71 in = 180.34 cm
- 72 in = 182.88 cm
- 73 in = 185.42 cm
- 74 in = 187.96 cm
- 75 in = 190.5 cm
- 76 in = 193.04 cm
- 77 in = 195.58 cm
- 78 in = 198.12 cm
- 79 in = 200.66 cm
- 80 in = 203.2 cm
- 81 in = 205.74 cm
- 82 in = 208.28 cm
- 83 in = 210.82 cm
- 84 in = 213.36 cm
- 85 in = 215.9 cm
- 86 in = 218.44 cm
- 87 in = 220.98 cm
- 88 in = 223.52 cm
- 89 in = 226.06 cm
- 90 in = 228.6 cm
- 91 in = 231.14 cm
- 92 in = 233.68 cm
- 93 in = 236.22 cm
- 94 in = 238.76 cm
- 95 in = 241.3 cm
- 96 in = 243.84 cm
- 97 in = 246.38 cm
- 98 in = 248.92 cm
- 99 in = 251.46 cm
- 100 in = 254 cm
- 125 in = 317.5 cm
- 150 in = 381 cm
- 175 in = 444.5 cm
- 200 in = 508 cm
- 225 in = 571.5 cm
- 250 in = 635 cm
- 275 in = 698.5 cm
- 300 in = 762 cm
- 325 in = 825.5 cm
- 350 in = 889 cm
- 375 in = 952.5 cm
- 400 in = 1,016 cm
- 425 in = 1,079.5 cm
- 450 in = 1,143 cm
- 475 in = 1,206.5 cm
- 500 in = 1,270 cm
- 550 in = 1,397 cm
- 600 in = 1,524 cm
- 650 in = 1,651 cm
- 700 in = 1,778 cm
- 750 in = 1,905 cm
- 800 in = 2,032 cm
- 850 in = 2,159 cm
- 900 in = 2,286 cm
- 950 in = 2,413 cm
- 1,000 in = 2,540 cm
- 1,500 in = 3,810 cm
- 2,000 in = 5,080 cm
- 2,500 in = 6,350 cm
- 3,000 in = 7,620 cm
- 3,500 in = 8,890 cm
- 4,000 in = 10,160 cm
- 4,500 in = 11,430 cm
- 5,000 in = 12,700 cm
- 5,500 in = 13,970 cm
- 6,000 in = 15,240 cm
- 6,500 in = 16,510 cm
- 7,000 in = 17,780 cm
- 7,500 in = 19,050 cm
- 8,000 in = 20,320 cm
- 8,500 in = 21,590 cm
- 9,000 in = 22,860 cm
- 9,500 in = 24,130 cm
- 10,000 in = 25,400 cm
1 inch = 2.54 cm exactly, fixed by the 1959 international yard and pound agreement adopted by the US, UK, Canada, Australia and New Zealand. Methodology & sources.
Frequently asked questions
How many centimeters is 1 inch?
1 inch is exactly 2.54 centimeters. Unlike most conversion factors, this one is an exact definition rather than a rounded measurement.
How do I read a TV size in inches?
The inch figure is the screen diagonal, not its width. A 55-inch TV measures 139.7 cm diagonally but only about 121 cm wide in 16:9 format. Always check the width before buying furniture for it.
Why do inches persist in metric countries?
Screen diagonals, car rims, bike frames and plumbing diameters remain standardised in inches worldwide, a legacy of Anglo-American industrial standards that became the international reference in those specific sectors.
Why doesn't a 2 by 4 measure 2 by 4 inches?
Because the stated size is that of the rough timber, before drying and planing. A North American 2×4 leaves the mill at 2 by 4 inches and reaches you at 1.5 by 3.5, that is 38 by 89 millimetres. The gap is a naming convention rather than a deception, and it is worth knowing before ordering a cut.
How do I read fractions of an inch?
American rulers and tools divide the inch into sixteenths rather than decimals. A sixteenth is 1.5875 mm, an eighth 3.175 mm, a quarter 6.35 mm and a half 12.7 mm. A 3/8 inch dimension is therefore 9.525 mm, and 5/16 is 7.9375: round values on one side are never round on the other.