CM to Inches Converter
To convert centimetres to inches, divide the number of centimetres by 2.54. One inch is exactly 2.54 cm, so 10 cm is 3.94 inches, 25 cm is 9.84 inches and 100 cm is 39.37 inches. You can also multiply by 0.3937 for the same result.
Type any value into the converter below and the answer updates as you type. For other units use the length converter. Underneath you will find the formula, a chart from 1 cm to 200 cm, worked examples, tape-measure fractions and the mistakes to avoid.
CM to inches converter
centimetres (cm)= inches (in)On a tape measure: about 3 15/16 in
How do you convert cm to inches?
To convert cm to inches, divide the length in centimetres by 2.54. The number 2.54 is not rounded: the inch is defined as exactly 2.54 centimetres, so the formula is exact and only your final rounding adds error.
inches = centimetres / 2.54
The method takes three steps:
- Write down the length in centimetres, for example 25 cm.
- Divide by 2.54: 25 / 2.54 = 9.8425.
- Round to the precision you need: 9.84 in to two decimal places, or about 9 13/16 in on a tape measure.
If you prefer to multiply, use 0.3937 instead: 25 x 0.3937 = 9.8425. Both routes give the same answer, because 1 / 2.54 = 0.393701 to six decimal places.
On a 12 cm ruler, the 10 cm mark sits just short of the 4-inch mark, because 10 cm is 3.94 in.
Centimetres to inches chart
Inches are rounded to two decimal places. The tape-measure column gives the nearest sixteenth of an inch, which is the finest marking on most British and American tape measures.
| Centimetres | Inches | Nearest 1/16 in | Feet and inches |
|---|---|---|---|
| 1 cm | 0.39 in | 3/8 in | – |
| 2 cm | 0.79 in | 13/16 in | – |
| 3 cm | 1.18 in | 1 3/16 in | – |
| 4 cm | 1.57 in | 1 9/16 in | – |
| 5 cm | 1.97 in | 1 15/16 in | – |
| 6 cm | 2.36 in | 2 3/8 in | – |
| 7 cm | 2.76 in | 2 3/4 in | – |
| 8 cm | 3.15 in | 3 1/8 in | – |
| 9 cm | 3.54 in | 3 9/16 in | – |
| 10 cm | 3.94 in | 3 15/16 in | – |
| 12 cm | 4.72 in | 4 3/4 in | – |
| 15 cm | 5.91 in | 5 7/8 in | – |
| 20 cm | 7.87 in | 7 7/8 in | – |
| 25 cm | 9.84 in | 9 13/16 in | – |
| 30 cm | 11.81 in | 11 13/16 in | – |
| 40 cm | 15.75 in | 15 3/4 in | 1 ft 3.7 in |
| 50 cm | 19.69 in | 19 11/16 in | 1 ft 7.7 in |
| 60 cm | 23.62 in | 23 5/8 in | 1 ft 11.6 in |
| 70 cm | 27.56 in | 27 9/16 in | 2 ft 3.6 in |
| 75 cm | 29.53 in | 29 1/2 in | 2 ft 5.5 in |
| 80 cm | 31.50 in | 31 1/2 in | 2 ft 7.5 in |
| 90 cm | 35.43 in | 35 7/16 in | 2 ft 11.4 in |
| 100 cm | 39.37 in | 39 3/8 in | 3 ft 3.4 in |
| 120 cm | 47.24 in | 47 1/4 in | 3 ft 11.2 in |
| 150 cm | 59.06 in | 59 1/16 in | 4 ft 11.1 in |
| 160 cm | 62.99 in | 63 in | 5 ft 3 in |
| 165 cm | 64.96 in | 64 15/16 in | 5 ft 5 in |
| 170 cm | 66.93 in | 66 15/16 in | 5 ft 6.9 in |
| 175 cm | 68.90 in | 68 7/8 in | 5 ft 8.9 in |
| 180 cm | 70.87 in | 70 7/8 in | 5 ft 10.9 in |
| 190 cm | 74.80 in | 74 13/16 in | 6 ft 2.8 in |
| 200 cm | 78.74 in | 78 3/4 in | 6 ft 6.7 in |
Worked examples from around the house
- A4 paper: 21 cm × 29.7 cm. Divide each by 2.54 to get 8.27 in × 11.69 in, which is why A4 is slightly narrower and longer than US Letter (8.5 in × 11 in).
- A 30 cm ruler: 30 ÷ 2.54 = 11.81 in, roughly 11 13/16 in on a tape. It falls about 3/16 in short of a foot.
- Waist size: 81 cm ÷ 2.54 = 31.89 in, which a clothing label rounds to a 32-inch waist. 86 cm is 33.86 in (34 in) and 91 cm is 35.83 in (36 in).
- Height: 165 cm ÷ 2.54 = 64.96 in. Divide by 12 to get 5 ft 4.96 in, usually given as 5 ft 5 in. Use the feet to cm converter to go the other way.
Reading the answer on a tape measure
A decimal answer such as 9.84 in is hard to find on a tape, because imperial tapes are marked in halves, quarters, eighths and sixteenths rather than tenths. To convert the decimal part, multiply it by 16 and round to the nearest whole number: 0.84 × 16 = 13.4, so 9.84 in sits at about 9 13/16 in. Simplify the fraction where you can, so 8/16 becomes 1/2 and 4/16 becomes 1/4. For the full list of fractions see our inches to mm fractions chart.
Common mistakes to avoid
- Multiplying instead of dividing. Going from cm to inches the number must get smaller. If 10 cm turns into 25.4, you have multiplied by 2.54 and converted the wrong way.
- Rounding too early. Dividing by 2.5 instead of 2.54 is 1.6 per cent out, which adds up to almost 2 cm over a 1 metre run of skirting board or worktop.
- Mixing up millimetres and centimetres. Many UK product sheets give sizes in mm. Divide millimetres by 25.4, not 2.54, or convert to cm first.
- Treating 5.5 ft as 5 ft 5 in. Half a foot is 6 inches, so 5.5 ft is 5 ft 6 in. Keep feet and inches separate when you convert heights.
Frequently asked questions
How many inches is 1 cm?
One centimetre is 0.3937 inches, a little under four tenths of an inch. It takes 2.54 cm to make one inch.
How many inches is 30 cm?
30 cm is 11.81 inches, just short of a foot. A standard 30 cm school ruler is therefore slightly shorter than a 12-inch ruler.
Is 2.54 an exact conversion factor?
Yes. Since the international yard and pound agreement of 1959, the inch has been defined as exactly 2.54 centimetres. Only the rounding of your answer introduces any error.
How do I convert cm to feet and inches?
Divide the centimetres by 2.54 to get inches, then divide by 12. The whole number is feet and the remainder is inches. For example, 165 cm is 64.96 in, which is 5 ft 5 in.
What is the quickest way to estimate cm to inches?
Multiply by 4 and divide by 10. 25 cm becomes 10 inches against a true 9.84 in, which is close enough for a rough check but about 1.6 per cent high.
Why do UK clothes use both cm and inches?
UK retailers are required to show metric measurements, but many shoppers still think of waist and inside leg in inches, so labels often give both. A 32-inch waist is 81 cm.
Related converters
Need more than a number? Our length conversion guides cover height in feet and cm, fractions of an inch and room sizes, with worked examples and reference charts.
Sources
- SI units: length (NIST Office of Weights and Measures)
- Weights and Measures Act 1985, Schedule 1 (legislation.gov.uk)