To convert cm to inches, divide by 2.54: one inch is exactly 2.54 centimeters, so 1 cm ≈ 0.393701 in. For example, 15 cm = 5.9055 in, and 30 cm = 11.811 in, just under a foot.
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How to use the cm to inches converter
- Enter the length in centimeters, for example 12.
- Read the cm to inches converter result: 12 cm ÷ 2.54 = 4.7244 in.
- For a tape measure, round to the nearest 1/16 in: about 4 3/4 in.
What is the CM to inches formula?
inches = centimeters ÷ 2.54 (≈ × 0.393701)
The reverse is centimeters = inches × 2.54.
The inch, foot, yard and mile are defined exactly in meters (1 in = 2.54 cm, 1 ft = 0.3048 m, 1 yd = 0.9144 m, 1 mi = 1,609.344 m), so these factors are exact. The multiplier 0.393701 is rounded to six significant digits; the calculator uses the full-precision value.
What are centimeters and inches?
Length measures distance. The SI base unit is the meter. Since 1959 the international inch has been defined as exactly 2.54 cm, so the foot is exactly 0.3048 m and the mile exactly 1,609.344 m.
- Centimeter (cm): 1 cm = 0.01 m (Metric unit).
- Inch (in): 1 in = 0.0254 m (US/Imperial unit).
Cm to inches worked examples
- A 15 cm ruler: 15 ÷ 2.54 = 5.90551 in
- A 30 cm (A4-width-plus) shelf: 30 ÷ 2.54 = 11.811 in
- A height of 170 cm: 170 ÷ 2.54 = 66.9291 in
Conversion chart
| cm | in | cm | in |
|---|---|---|---|
| 1 | 0.3937 | 30 | 11.811 |
| 2 | 0.7874 | 40 | 15.748 |
| 2.5 | 0.9843 | 50 | 19.685 |
| 5 | 1.9685 | 60 | 23.622 |
| 10 | 3.937 | 75 | 29.5276 |
| 15 | 5.9055 | 100 | 39.3701 |
| 20 | 7.874 | 150 | 59.0551 |
| 25 | 9.8425 | 200 | 78.7402 |
Values are rounded to four decimal places, or two for results of 100 or more.
Quick mental conversion
Multiply by 0.4 for a quick estimate (it overstates by about 1.6%): 30 cm ≈ 12 in.
Centimeters to feet and inches for height
| Height (cm) | Feet and inches | Total inches |
|---|---|---|
| 150 | 4 ft 11.1 in | 59.1 |
| 160 | 5 ft 3.0 in | 63.0 |
| 165 | 5 ft 5.0 in | 65.0 |
| 170 | 5 ft 6.9 in | 66.9 |
| 175 | 5 ft 8.9 in | 68.9 |
| 180 | 5 ft 10.9 in | 70.9 |
| 185 | 6 ft 0.8 in | 72.8 |
| 190 | 6 ft 2.8 in | 74.8 |
To split a height: total inches = cm ÷ 2.54; feet = whole part of (inches ÷ 12); remaining inches = inches − feet × 12.
Centimeters from inches: reverse chart
Going the other way, centimeters = inches × 2.54. Common values:
| inches | centimeters |
|---|---|
| 1 | 2.54 |
| 2 | 5.08 |
| 5 | 12.7 |
| 10 | 25.4 |
| 20 | 50.8 |
| 50 | 127 |
| 100 | 254 |
| 500 | 1,270 |
| 1,000 | 2,540 |
Centimeter to inch fractions
Tape measures in the US are marked in fractions of an inch. Each value rounded to the nearest 1/16 in (0.0625 in):
| cm | inches | nearest 1/16 in |
|---|---|---|
| 1 | 0.3937 | 3/8 in |
| 2 | 0.7874 | 13/16 in |
| 2.5 | 0.9843 | 1 in |
| 3 | 1.1811 | 1 3/16 in |
| 5 | 1.9685 | 1 15/16 in |
| 7.5 | 2.9528 | 2 15/16 in |
| 10 | 3.937 | 3 15/16 in |
| 15 | 5.9055 | 5 7/8 in |
| 20 | 7.874 | 7 7/8 in |
| 30 | 11.811 | 11 13/16 in |
Rounding to 1/16 in can be off by up to 1/32 in (about 0.8 mm).
Paper sizes in inches
ISO 216 paper sizes are defined in millimeters. A4 is 21.0 × 29.7 cm, or about 8.27 × 11.69 in, slightly narrower and longer than US Letter at 8.5 × 11 in (21.59 × 27.94 cm). A5 is 14.8 × 21.0 cm, about 5.83 × 8.27 in. Use the inches to cm converter for the reverse and the cm to feet converter for heights.
Clothes and luggage
Size charts and luggage rules are where cm to inches comes up most. A chest measurement of 96 cm is 37.8 inches, so it sits between a 37 and 38 inch size. An inseam of 81 cm is 31.9 inches, which a US store would list as 32. For borderline cases, check the brand’s own chart, since fit varies more than the rounding does.
Airline cabin bag limits are often 55 × 40 × 20 cm. A cm to inches conversion gives about 21.7 × 15.7 × 7.9 inches. US carriers commonly quote 22 × 14 × 9 inches, so a bag that just meets the European limit may be too wide for a US flight. Measure wheels and handles too; they count.
Shoe insoles and gloves are also measured this way. A foot length of 26.5 cm is about 10.4 inches, and many brands size from that figure rather than from a printed shoe size, so it is worth measuring at home with a ruler against a wall.
Related converters and calculators
Related conversions:
- Inches to cm: in to cm
- mm to inches: mm to in
- cm to feet: height
- Feet to cm: ft to cm
- Length converter: all length units
Sources
NIST Special Publication 811, Appendix B; NIST: SI units – length.
Questions about this calculator
How many inches are in a cm?
0.393701 in; 1 in = 2.54 cm exactly.
How do I convert cm to inches?
Divide by 2.54. For example, 20 cm = 7.874 in.
What is 5 cm in inches?
1.9685 in, about 1 15/16 in.
How do I get a cm to inches fraction?
Divide by 2.54, multiply the decimal part by 16 and round: 10 cm = 3.937 in ≈ 3 15/16 in.
What is A4 in inches?
About 8.27 × 11.69 in.
Check the assumptions and units before relying on a result. Financial, tax and health estimates do not replace advice for your individual circumstances.
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