Centimeters to Inches Converter
To convert centimeters to inches, divide by 2.54. One international inch is exactly 2.54 centimeters, fixed by the 1959 international yard and pound agreement.
Formula
inches = centimeters ÷ 2.54
Equivalently:
inches = centimeters × 0.3937007874015748
Reverse:
centimeters = inches × 2.54
Formula variables
- centimeters — length in centimeters (cm).
- inches — equivalent length in inches (in).
- 2.54 — the exact number of centimeters in one international inch, defined by the 1959 international yard and pound agreement.
Worked Examples
Example 1: 1 centimeter to inches
- Start: 1 cm.
- Divide: 1 ÷ 2.54 = 0.3937007874015748.
- Result: 1 cm ≈ 0.3937 inches.
Example 2: 30 centimeters to inches
- Start: 30 cm.
- Divide: 30 ÷ 2.54 = 11.811023622047244.
- Result: 30 cm ≈ 11.811 inches. 30 cm is a common ruler length (about 11.8 inches).
Example 3: 180 centimeters to inches
- Start: 180 cm.
- Divide: 180 ÷ 2.54 = 70.86614173228347.
- Result: 180 cm ≈ 70.866 inches. In feet and inches, that is 5' 10.87" — a common adult height.
Common Conversion Table
| Centimeters (cm) | Inches (in) |
|---|---|
| 1 | 0.393701 |
| 2.54 | 1.000000 |
| 5 | 1.968504 |
| 10 | 3.937008 |
| 20 | 7.874016 |
| 30 | 11.811024 |
| 50 | 19.685039 |
| 100 | 39.370079 |
| 150 | 59.055118 |
| 200 | 78.740157 |
Real-World Uses
- Height measurement: Centimeters are used for height in most of the world; inches (and feet) are used in the US and UK, so conversions are routine.
- Paper and print: Paper sizes like A4 (21 × 29.7 cm) are sometimes referenced in inches for US audiences (8.27 × 11.69 in).
- Clothing sizes: Body measurements are often given in centimeters outside the US; converting to inches helps US-based shoppers interpret foreign size charts.
- Electronics and screens: Screen diagonals and component dimensions are frequently quoted in both systems.
Unit Definitions
Centimeter (cm)
A decimal submultiple of the meter, equal to exactly 0.01 meters. Widely used in everyday measurement throughout most countries.
Inch (in)
The international inch is defined as exactly 2.54 centimeters. This definition was fixed by the 1959 international yard and pound agreement and is used in the United States, the United Kingdom, and a small number of other countries for everyday measurements.
Accuracy and Rounding
Because 1 in = 2.54 cm exactly, the conversion is exact in decimal form for any centimeter input expressible as a terminating decimal. Display precision scales with input magnitude; for most purposes 4 significant figures are more than enough.
Related Converters
- Inches to Centimeters — the reverse conversion
- Meters to Feet
- Feet to Meters
- All Length Converters
Frequently Asked Questions
How many inches are in a centimeter?
One centimeter equals approximately 0.3937 inches. The exact factor is 1 / 2.54 = 0.3937007874015748...
How do you convert cm to inches?
Divide the centimeter value by 2.54. For example, 30 cm ÷ 2.54 ≈ 11.811 inches.
How many inches is 180 cm?
180 centimeters equals approximately 70.866 inches, which is about 5 feet 10.9 inches.
Is 1 inch exactly 2.54 cm?
Yes. Since 1959, the international inch has been defined as exactly 2.54 centimeters by international agreement.