To convert centimeters to inches, divide by 2.54. So 30 cm = 11.811 in. The factor is exact - one inch is defined as exactly 2.54 cm since the International Yard and Pound Agreement of 1959.
- Exact factor: 1 in = 2.54 cm (international definition, fixed in 1959).
- 1 cm = 0.393701 in - roughly 4/10 of an inch.
- Quick mental check: multiply cm by 0.4 for a fast estimate (1.6% high).
- Screen sizes are marketed in inches in most countries - converting from cm spec sheets is a common need.
How to Use This Converter
Type any value in the cm field and the inches result appears instantly. You can also type in the inches field to convert back to cm - it works in both directions without pressing a button.
How Do You Convert Centimeters to Inches?
Divide centimeters by 2.54. This is exact: 2.54 is the defined number of centimeters per inch, fixed in 1959. Alternatively, multiply by 0.393701 (the reciprocal of 2.54, rounded to 6 decimal places).
$$\text{in} = \text{cm} \div 2.54$$
Worked examples: 10 cm = 3.937 in. 50 cm = 19.685 in. 100 cm = 39.370 in.
How Do You Convert Inches to Centimeters?
Multiply inches by 2.54. For a full multi-unit converter, the length converter handles all metric and imperial units at once.
$$\text{cm} = \text{in} \times 2.54$$
Worked examples: 6 in = 15.24 cm. 12 in = 30.48 cm. 36 in = 91.44 cm.
Centimeters to Inches Reference Table
Common body measurements, screen sizes, and clothing dimensions converted using the exact factor 1 ÷ 2.54.
| Centimeters | Inches | Common context |
|---|---|---|
| 1 cm | 0.394 in | Small button |
| 10 cm | 3.937 in | Smartphone width |
| 15.24 cm | 6 in | Half a foot |
| 25.4 cm | 10 in | Tablet screen |
| 30 cm | 11.811 in | Standard ruler |
| 33.02 cm | 13 in | Small laptop |
| 39.62 cm | 15.6 in | Standard laptop |
| 60.96 cm | 24 in | Desktop monitor |
| 68.58 cm | 27 in | Large monitor |
| 139.7 cm | 55 in | Large TV |
When Do You Need to Convert cm to Inches?
Centimeters are the standard unit for small measurements in metric countries, while inches remain common in the US and for specific product categories globally. Converting between the two is routine for anyone buying US-market electronics, clothing, or hardware from abroad.
- Screen sizes - global spec sheets often list dimensions in both cm and inches; US retailers primarily list inches.
- Clothing - EU waist/inseam in cm vs US sizing in inches.
- Height - medical records in cm need converting to feet and inches for US formats.
- Hardware - drill bits and pipe fittings in mm/cm vs US inch fractions.
Frequently Asked Questions
How many inches is 1 cm?
0.393701 inches. That's 1 ÷ 2.54. In fractions: approximately 25/64 of an inch. A centimeter is 10 millimeters; 1 inch is 25.4 millimeters. So 1 cm is slightly less than half an inch.
How do you convert cm to inches?
Divide by 2.54. Quick mental estimate: multiply by 0.4 (gives a result 1.6% too high). For 30 cm: 30 × 0.4 = 12, actual is 11.811 in. The difference is about 5 mm - fine for casual use but not engineering.
How many inches is 170 cm?
66.93 inches, or 5 feet 6.93 inches. Divide 170 by 2.54 = 66.929 in. To convert to feet: 66 ÷ 12 = 5 ft with 6.929 in remaining. Use the height converter for feet-and-inches output directly.
What is 5 foot 7 in cm?
170.18 cm. Convert to total inches: 5 × 12 + 7 = 67 in. Multiply by 2.54: 67 × 2.54 = 170.18 cm. If you need to convert the other direction (cm to feet and inches), the height converter handles that format automatically.