How do I convert cm to inches?
Since 1 inch is defined as exactly 2.54 cm, converting centimetres to inches means dividing the centimetre value by 2.54, or multiplying it by 0.393701. For example, 30 cm divided by 2.54 is about 11.81 inches. Enter any length in centimetres in FixDoks's CM to Inches converter to get the exact result and a quick reference chart.
CM to Inches at a glance
| Formula | inches = centimetres / 2.54 |
|---|---|
| Example | 30 cm = 11.81 inches |
| Processing | In your browser; your files are not uploaded |
| Price | Free |
| Works on | Chrome, Edge, Safari and Firefox on Windows, Mac, Android and iPhone |
How to use CM to Inches Converter
- Type the length in centimetres in the Value box.
- Read the result in inches straight away.
- Use the ⇄ button if you want to convert inches to cm instead.
How do I convert cm to inches?
The inch has been defined as exactly 2.54 centimetres since 1959, so the conversion is exact:
inches = centimetres ÷ 2.54, or equivalently inches = centimetres × 0.393701
Worked examples
- 30 cm ÷ 2.54 = 11.81 inches, about the length of a school ruler.
- 15.6 cm is not a laptop size. Laptop screens are measured in inches diagonally: a 15.6 inch screen is 15.6 × 2.54 = 39.6 cm.
- A waist of 81 cm ÷ 2.54 = 31.9 inches, which is a size 32 in most jeans.
- 170 cm ÷ 2.54 = 66.93 inches. Divide by 12 to get feet: 5 feet 6.9 inches.
Quick mental method
Dividing by 2.54 in your head is awkward. Multiply by 4 and divide by 10 for a close estimate: 30 cm × 4 = 120, ÷ 10 = 12 inches (exact answer 11.81). The estimate is about 1.6% high, fine for shopping but not for engineering.
Where you will meet cm and inches
- Clothing: Indian and European sizes use cm, US and UK brands often use inches for waist and chest.
- Screens: TV, monitor and phone sizes are sold in inches worldwide, including in India.
- Tailoring: Indian tailors usually measure in inches, while ready-made size charts list cm.
- Paper and photos: A4 is 21 × 29.7 cm, or 8.27 × 11.69 inches. Passport photos in India are 3.5 × 4.5 cm, about 1.38 × 1.77 inches.
- Rainfall: Indian weather reports use mm and cm, American reports use inches.
Common conversions
| cm | inches |
|---|---|
| 10 | 3.94 |
| 25 | 9.84 |
| 50 | 19.69 |
| 75 | 29.53 |
| 100 | 39.37 |
| 150 | 59.06 |
cm, mm and inches together
1 cm = 10 mm, so 1 inch = 25.4 mm. Rulers often show cm on one edge and inches on the other, with each inch split into 16 parts. One sixteenth of an inch is about 1.59 mm.
How precise should the answer be?
For clothing and furniture, one decimal place is plenty. For engineering drawings and 3D printing, keep at least three decimals, or work in millimetres from the start. The calculator shows up to ten significant digits so you can round to whatever your job needs.
How do I convert inches back to cm?
Multiply inches by 2.54. A 32 inch waist is 81.3 cm, a 43 inch TV is 109.2 cm across the diagonal, and a 6 inch phone screen is 15.2 cm. Tap the swap button above to switch the direction, and the quick table below the result changes too.
For heights in feet and inches, the Feet to CM converter handles the feet and inches split for you.