What is the Cm to Inches Calculator?
This calculator converts a length given in centimeters (cm) into inches. The centimeter is a metric unit of length, while the inch is an imperial/US customary unit. The conversion is based on the internationally agreed definition that one inch is exactly 2.54 centimeters. This relationship is exact, so the conversion introduces no rounding error beyond what you choose to display.
How to use it
Enter the length you want to convert in the "Centimeters" field and the calculator instantly returns the equivalent length in inches. You can enter whole numbers or decimals (for example 15.5 cm). The result is shown to several decimal places so you can round as needed for your project.
The formula explained
The core formula is simply:
$$\text{inches} = \frac{\text{cm}}{2.54}$$
Because 1 inch equals 2.54 cm by definition, dividing a centimeter value by 2.54 gives the number of inches. To convert the other direction, multiply inches by 2.54 to recover centimeters: \(\text{cm} = \text{inches} \times 2.54\).
Worked example
Suppose you have a measurement of 100 cm and want it in inches. Divide: $$100 \div 2.54 = 39.3701 \text{ inches}$$ So 100 centimeters is approximately 39.37 inches — close to one yard. A common height of 180 cm converts to \(180 \div 2.54 = 70.866\) inches, or about 5 feet 11 inches.
FAQ
How many inches is 1 cm? One centimeter equals \(1 \div 2.54 = 0.3937\) inches.
Is the conversion factor exact? Yes. Since 1959 an inch has been defined as exactly 2.54 centimeters, so the conversion is exact.
How do I convert inches back to cm? Multiply the number of inches by 2.54. For example, \(12 \text{ inches} \times 2.54 = 30.48 \text{ cm}\).
