Cm to Inches Converter
Need to convert cm to inches? Our free two-way converter works in both directions: type a length in centimeters and the inches update instantly — or type inches and get centimeters back. Handy for heights, screen sizes, and DIY measurements, it also shows the feet-and-inches breakdown (so you can read off your height) on a live ruler display.
Enter your numbers
Your results
| Feet + inches | — |
| Millimeters | — |
| Formula | 1 in = 2.54 cm exactly |
Quick reference: cm to inches
| Centimeters | Inches |
|---|---|
| 1 cm | 0.3937 in |
| 5 cm | 1.9685 in |
| 10 cm | 3.937 in |
| 30 cm | 11.811 in |
| 50 cm | 19.685 in |
| 100 cm | 39.3701 in |
| 150 cm | 59.0551 in |
| 200 cm | 78.7402 in |
Exact conversions: 1 inch is defined as exactly 2.54 cm, so displayed values are rounded only for readability.
How to use this calculator
Type a length in the centimeters box and the inches box updates instantly — or type in the inches box and the centimeters update instead. Use the quick-pick chips for common lengths, or glance at the quick reference table. The ruler shows your value on dual cm and inch scales, and the results panel gives the feet-and-inches breakdown for heights.
For heights, enter your height in centimeters (e.g. 180 cm) and read the feet + inches row: 180 cm is 5 ft 10.8661 in, about 5 ft 10.9 in. Going the other way, type your height in inches — 72 in gives exactly 182.88 cm.
How it works
The conversion is built on a single exact factor: 1 inch = 2.54 centimeters. This isn't a rounded approximation — the international yard and pound agreement of 1959 defined the inch as exactly 2.54 cm, a definition still in force today. Because the factor is exact, every result this tool produces is exact too; we only round the displayed digits for readability.
The math is simple division and multiplication: inches = cm ÷ 2.54 and cm = inches × 2.54. The feet-and-inches breakdown divides the inches by 12, keeps the whole number as feet, and shows the remainder as inches — so 39.3701 in becomes 3 ft 3.3701 in.
Frequently asked questions
What is the formula to convert cm to inches?
Divide centimeters by 2.54: inches = cm ÷ 2.54. For example, 100 cm ÷ 2.54 = 39.3701 inches. To convert the other way, multiply inches by 2.54: cm = inches × 2.54.
Is 2.54 cm per inch exact or approximate?
It is exact. The international yard and pound agreement of 1959 defined the inch as exactly 2.54 centimeters, so this converter's results are exact to the limits of the displayed decimals — 2.54 cm is precisely 1 inch.
How do I convert cm to feet and inches for height?
First convert cm to inches (divide by 2.54), then divide the inches by 12: the whole number is the feet and the remainder is the inches. For example, 180 cm = 70.8661 in = 5 ft 10.8661 in (about 5 ft 10.9 in). This converter shows the feet-and-inches breakdown automatically.
How do I convert inches to cm?
Multiply the inches by 2.54. For example, 72 in × 2.54 = 182.88 cm. Type a value in the inches field above and the centimeters update instantly.
What is the difference between mm and cm when converting to inches?
One centimeter equals 10 millimeters. To convert millimeters to inches, divide by 25.4 (10 × 2.54). For example, 100 mm = 10 cm = 3.937 inches.