Instant Unit Conversion
Convert Inches to Centimeters (in to cm)
Exact formula, conversion factors, live calculator, and reference charts for inches to centimeters.
Method reviewed:Exact defined factors — international yard and pound (1959), US customary gallon and cup, SI — the values NIST SP 811 lists · reviewed September 2026 · Source: NIST SP 811
1 inch is equal to exactly 2.54 centimeters. To convert inches to centimeters, multiply the inch value by 2.54.
Live Inches to Centimeters Calculator
cm = in × 2.54Open full length converter →Inches to Centimeters Conversion Table
Quick reference conversion chart from 1 to 100 inches.
| Inches (in) | Centimeters (cm) | Mathematical Formula |
|---|---|---|
| 1 in | 2.54 cm | 1 × 2.54 |
| 2 in | 5.08 cm | 2 × 2.54 |
| 5 in | 12.7 cm | 5 × 2.54 |
| 10 in | 25.4 cm | 10 × 2.54 |
| 15 in | 38.1 cm | 15 × 2.54 |
| 20 in | 50.8 cm | 20 × 2.54 |
| 25 in | 63.5 cm | 25 × 2.54 |
| 50 in | 127 cm | 50 × 2.54 |
| 75 in | 190.5 cm | 75 × 2.54 |
| 100 in | 254 cm | 100 × 2.54 |
Frequently Asked Questions
How many cm in an inch?
There are exactly 2.54 centimeters in 1 inch.
How many cm is 12 inches?
12 inches is exactly 30.48 cm — one international foot, defined in 1959 alongside the inch.
Why is the inch defined in metric terms?
Since the 1959 international yard and pound agreement, the inch has been defined as exactly 25.4 mm. The US customary inch is legally a metric derivative, which is why inch–centimeter conversions are exact rather than approximate.