To convert inches to centimeters, multiply by 2.54. So 1 in = 2.54 cm. The factor is exact - one inch is defined as exactly 2.54 centimeters since the International Yard and Pound Agreement of 1959.
- Exact factor: 1 in = 2.54 cm (international definition, fixed in 1959).
- 1 foot = 12 inches = 30.48 cm.
- Quick mental check: multiply inches by 2.5 for a close estimate (1.6% low).
- TV and monitor screen sizes are specified in inches in most markets - converting to cm is routine outside the US.
How to Use This Converter
Type any value in the inches field and the cm result appears instantly. You can also type in the cm field to convert back to inches - it works in both directions without pressing a button.
How Do You Convert Inches to Centimeters?
Multiply inches by 2.54. This factor is exact: one inch is defined as precisely 2.54 centimeters under the International Yard and Pound Agreement of 1959. No rounding is introduced by the conversion factor itself.
$$\text{cm} = \text{in} \times 2.54$$
Worked examples: 6 in = 15.24 cm. 12 in = 30.48 cm. 36 in = 91.44 cm.
Mental shortcut: multiply by 2.5 for a quick estimate. The result is 1.6% low - for a 10-inch screen that gives 25 cm instead of 25.4 cm, a 4 mm difference.
How Do You Convert Centimeters to Inches?
Divide centimeters by 2.54, or multiply by 0.393701. For a full multi-unit converter, the length converter handles all units at once.
$$\text{in} = \text{cm} \div 2.54$$
Worked examples: 10 cm = 3.937 in. 30 cm = 11.811 in. 100 cm = 39.37 in.
Inches to Centimeters Reference Table
Common screen sizes, clothing dimensions, and body measurements converted using the exact factor 2.54.
| Inches | Centimeters | Common context |
|---|---|---|
| 1 in | 2.54 cm | Thumb width approx. |
| 6 in | 15.24 cm | Half a foot ruler |
| 12 in | 30.48 cm | 1 foot / ruler length |
| 13 in | 33.02 cm | Small laptop screen |
| 15.6 in | 39.62 cm | Standard laptop screen |
| 24 in | 60.96 cm | Desktop monitor |
| 27 in | 68.58 cm | Large desktop monitor |
| 32 in | 81.28 cm | Small TV |
| 55 in | 139.7 cm | Large TV |
| 65 in | 165.1 cm | Extra-large TV |
When Do You Need to Convert Inches to Centimeters?
Inches are used in the US and, to some extent, the UK for specific measurements such as screen sizes, waist measurements, and some hardware dimensions. According to NIST (2023), most countries use centimeters for these everyday measurements.
- Screen sizes - TVs, monitors, and phones are marketed in inches globally. European retailers typically also list the cm equivalent.
- Clothing - waist and inseam measurements are in inches for US and UK brands; EU sizing uses centimeters.
- Tools and hardware - drill bits, pipe diameters, and fasteners in the US are in inches; European equivalents are in mm.
- Height - body height in feet and inches needs converting to cm for international medical records.
Frequently Asked Questions
How many cm is 1 inch?
Exactly 2.54 centimeters. This is an internationally fixed definition, not an approximation. It was established in 1959 and is the anchor point for all imperial-to-metric length conversions. A centimeter is 10 millimeters; an inch is 25.4 millimeters.
How do you convert inches to centimeters?
Multiply by 2.54. Since the factor is exact, the only rounding in your result comes from the number of decimal places you choose to display. Quick mental estimate: multiply by 2.5 (1.6% low). For 10 inches that's 25 cm; the correct answer is 25.4 cm.
How many inches is 30 cm?
30 cm = 11.811 inches. Divide by 2.54: 30 ÷ 2.54 = 11.811 in. A standard 30 cm ruler is almost exactly 12 inches (one foot) - about 2 mm short. Use the cm to inches converter for the reverse direction.
How many cm is 5 feet 10 inches?
177.8 cm. Convert to total inches first: 5 × 12 + 10 = 70 in. Multiply by 2.54: 70 × 2.54 = 177.8 cm. For mixed feet-and-inches inputs, the height converter handles this automatically.