Convert centimeters to inches (cm to in)
To convert centimeters to inches, divide the value in centimeters by 2.54 — the same as multiplying by about 0.393701. You will need it for TV and laptop screen sizes, US clothing and shoe charts, picture frames and any product listing that quotes inches. This cm to inches converter works both ways: type centimeters or inches into either box above and the other box, the worked formula and the chart below update as you type.
The centimeter (cm), or centimetre, is one hundredth of a meter. It belongs to the metric system that France introduced in the 1790s and that is now used almost everywhere. Centimeters are the everyday unit for body height, clothing and shoe measurements, paper sizes and furniture in India, Europe and most of the world. One centimeter is 0.393701 inches.
The inch (in or ″) is a unit of the imperial and US customary systems. Its name comes from the Latin uncia, “one twelfth”, and since the 1959 international yard and pound agreement it has been exactly 25.4 millimeters. Going the other way, one inch equals 2.54 centimeters. Inches measure TV, laptop and phone screens worldwide, as well as height, waist sizes, wheel rims and timber in the US.
How to convert cm to inches with this tool
- Type a number into the Centimeters (cm) box — it starts at 30 cm as an example.
- Read the answer in the Inches (in) box and in the result panel, which also shows the formula with your number.
- To go the other way, type into the inches box, or press the swap button to open the Inches to CM converter with your value carried over.
- Choose how many decimal places you want, or tap a quick value such as 10 cm, 30 cm, 100 cm.
- Press Copy result to paste the conversion into a message, spreadsheet or note.
CM to Inches converter features
Converts both ways
Type in the centimeters box to get inches, or in the inches box to get centimeters. The other box follows instantly.
Exact factor
Calculations use 1 in = 2.54 cm, and rounding is applied only to the answer you see — choose Auto or 0–10 decimal places.
Formula with your number
The working is shown under the result, for example 30 cm ÷ 2.54 = 11.811 in, so you can check it or copy the method.
Quick values and chart
Tap common values like 10 cm, 30 cm, 100 cm, or read the centimeters-to-inches table further down this page.
Feet and inches too
Under the answer you also see the length in feet and inches, such as 180 cm = 5 ft 10.9 in — the way heights are usually written.
CM to Inches formula
The formula is in = cm ÷ 2.54. It is exact because the inch has been defined as exactly 2.54 centimeters since 1959.
The reverse formula is cm = in × 2.54 — or use the Inches to CM converter. Three worked examples:
- A 30 cm school ruler: 30 cm ÷ 2.54 = 11.811 in
- The width of an A4 sheet (21 cm): 21 cm ÷ 2.54 = 8.2677 in
- A height of 180 cm: 180 cm ÷ 2.54 = 70.8661 in
CM to Inches quick reference
The values people look up most often, worked out with the exact factor:
- 1 cm = 0.393701 in
- 1 in = 2.54 cm
- 10 cm = 3.937 in
- 30 cm = 11.811 in
- 100 cm = 39.3701 in
- 150 cm = 59.0551 in
Quick tip: For a quick estimate, multiply by 4 and divide by 10: 30 cm × 0.4 ≈ 12 in, while the exact answer is 11.811 in. The shortcut overstates by about 1.6%.
Related conversions: MM to Inches, CM to Feet and the full length converter.
CM to Inches conversion table
Values in inches are rounded to 4 decimal places (more for very small numbers). For any value not listed, type it into the converter above.
| cm | in | cm | in |
|---|---|---|---|
| 1 | 0.3937 | 30 | 11.811 |
| 2 | 0.7874 | 35 | 13.7795 |
| 3 | 1.1811 | 40 | 15.748 |
| 4 | 1.5748 | 45 | 17.7165 |
| 5 | 1.9685 | 50 | 19.685 |
| 6 | 2.3622 | 55 | 21.6535 |
| 7 | 2.7559 | 60 | 23.622 |
| 8 | 3.1496 | 65 | 25.5906 |
| 9 | 3.5433 | 70 | 27.5591 |
| 10 | 3.937 | 75 | 29.5276 |
| 11 | 4.3307 | 80 | 31.4961 |
| 12 | 4.7244 | 85 | 33.4646 |
| 13 | 5.1181 | 90 | 35.4331 |
| 14 | 5.5118 | 95 | 37.4016 |
| 15 | 5.9055 | 100 | 39.3701 |
| 16 | 6.2992 | 110 | 43.3071 |
| 17 | 6.6929 | 120 | 47.2441 |
| 18 | 7.0866 | 150 | 59.0551 |
| 19 | 7.4803 | 180 | 70.8661 |
| 20 | 7.874 | 200 | 78.7402 |
| 25 | 9.8425 |
CM to Inches FAQ
How many inches is 15 cm?
15 centimeters is 5.9055 inches: 15 cm ÷ 2.54 = 5.9055 in.
How do I convert cm to inches?
Divide the value in centimeters by 2.54 — the same as multiplying by about 0.393701. For example, 100 cm ÷ 2.54 = 39.3701 in. To convert back, multiply the value in inches by 2.54 — or use the Inches to CM converter.
How many centimeters are in one inch?
One inch is 2.54 centimeters, because 1 in × 2.54 = 2.54 cm.
What is 100 centimeters in inches?
Is 1 inch exactly 2.54 cm?
Yes. Since 1959 the international inch has been defined as exactly 2.54 centimeters, so dividing by 2.54 gives an exact answer and any difference you see is only rounding. That is why 2.54 cm = 1 in with nothing left over.