How the conversion works
One inch is defined as exactly 2.54 cm (25.4 mm). To convert inches to centimetres, multiply by 2.54. To go the other way, divide by 2.54. Fractions first become decimals, so 3 5/8" = 3.625" = 9.2075 cm.
Inch fractions to millimetres chart
| Fraction | Decimal inch | mm |
|---|---|---|
| 1/16" | 0.0625 | 1.59 |
| 1/8" | 0.1250 | 3.17 |
| 3/16" | 0.1875 | 4.76 |
| 1/4" | 0.2500 | 6.35 |
| 5/16" | 0.3125 | 7.94 |
| 3/8" | 0.3750 | 9.52 |
| 7/16" | 0.4375 | 11.11 |
| 1/2" | 0.5000 | 12.70 |
| 9/16" | 0.5625 | 14.29 |
| 5/8" | 0.6250 | 15.88 |
| 11/16" | 0.6875 | 17.46 |
| 3/4" | 0.7500 | 19.05 |
| 13/16" | 0.8125 | 20.64 |
| 7/8" | 0.8750 | 22.22 |
| 15/16" | 0.9375 | 23.81 |
| 1" | 1.0000 | 25.40 |
Inches to centimetres chart
| Inches | cm | Inches | cm |
|---|---|---|---|
| 1" | 2.54 | 13" | 33.02 |
| 2" | 5.08 | 14" | 35.56 |
| 3" | 7.62 | 15" | 38.10 |
| 4" | 10.16 | 16" | 40.64 |
| 5" | 12.70 | 17" | 43.18 |
| 6" | 15.24 | 18" | 45.72 |
| 7" | 17.78 | 19" | 48.26 |
| 8" | 20.32 | 20" | 50.80 |
| 9" | 22.86 | 21" | 53.34 |
| 10" | 25.40 | 22" | 55.88 |
| 11" | 27.94 | 23" | 58.42 |
| 12" | 30.48 | 24" | 60.96 |
Centimetres to inches chart
| cm | Inches | Nearest 1/16" |
|---|---|---|
| 1 cm | 0.394 | 3/8" |
| 2 cm | 0.787 | 13/16" |
| 3 cm | 1.181 | 1 3/16" |
| 4 cm | 1.575 | 1 9/16" |
| 5 cm | 1.969 | 1 15/16" |
| 6 cm | 2.362 | 2 3/8" |
| 7 cm | 2.756 | 2 3/4" |
| 8 cm | 3.150 | 3 1/8" |
| 9 cm | 3.543 | 3 9/16" |
| 10 cm | 3.937 | 3 15/16" |
| 15 cm | 5.906 | 5 7/8" |
| 20 cm | 7.874 | 7 7/8" |
| 25 cm | 9.843 | 9 13/16" |
| 30 cm | 11.811 | 11 13/16" |
| 50 cm | 19.685 | 19 11/16" |
| 100 cm | 39.370 | 39 3/8" |
Frequently asked questions
How many cm is 5 feet 6 inches?
5 ft 6 in is 66 inches × 2.54 = 167.64 cm.
What is 1/8 inch in mm?
1/8" = 0.125" = 3.175 mm, usually rounded to 3.2 mm.
How do I enter a fraction?
Type it the way you would say it, for example 2 3/4, 2-3/4 or 3/16. The decimal, cm, mm and feet boxes update as you type.
Last reviewed 2026-10-07.