Convert centimeters to inches, both ways.
Type centimeters and read the exact inches, or type inches to convert back to centimeters. The result updates live, with feet, millimeters and meters for context and a one-click copy.
Your value
Edit either box. The formula is inches = cm divided by 2.54, and cm = inches times 2.54.
3.937 inWhat this means
Common cm to inches values
| Centimeters | Inches | Inches (rounded) | Rough guide |
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How the conversion works
The Centimeter-to-Inch Conversion Factor
One centimeter equals exactly 0.3937007874 inches. Equivalently, 1 inch = 2.54 cm, a defined, exact value since the international yard agreement of 1959. To convert centimeters to inches, divide by 2.54 or multiply by 0.3937. Quick mental math: 100 cm is about 39.4 inches, 25 cm is about 9.8 inches.
Why Both Units Still Exist
The metric system (centimeters) is used by most countries and all scientific work. The imperial system (inches) remains the official measurement in the United States and is widely used for clothing, screen sizes, and construction in the US and UK. Knowing both lets you read a tape measure, screen specification, or recipe from any source.
Common Reference Conversions
2.54 cm = 1 inch. 5 cm = 1.97 in (about 2 in). 10 cm = 3.94 in. 15 cm = 5.91 in. 30 cm = 11.81 in (about a foot). 100 cm = 39.37 in (one meter, slightly over a yard). Memorizing 2.54 lets you do mental math for any value.
When Precision Matters
For everyday measurements (clothing, room layout), rounding to one decimal is fine. For machining or technical drawings, use the full 4-decimal factor (0.3937). The calculator provides results to 4 decimal places by default.
Common questions
How many inches is 10 cm exactly?
10 cm equals 3.9370 inches (10 × 0.3937).
Why is 1 inch exactly 2.54 cm?
Since 1959 the international yard has been defined as exactly 0.9144 meters, which makes 1 inch = 25.4 mm = 2.54 cm by definition. It is no longer a measured value but a defined relationship.
What's the easiest way to estimate cm to inches?
Divide by 2.5 for a quick mental estimate. For exact values, divide by 2.54 or use this calculator. The estimate is accurate within 2%.
How do I convert in the other direction?
Multiply inches by 2.54 to get centimeters. We also offer an Inches to Centimeters converter for that direction.
Do tailors use cm or inches?
Depends on country. UK and US tailors typically use inches; most European tailors use cm. International size labels often list both.
All conversion runs in your browser. Nothing is uploaded. 1 inch is exactly 2.54 cm by international definition, so these results are precise, not approximate.