An inch is exactly 0.0254 meters.
Inches to Centimeters Converter — in to cm
Convert Inch (in) to Centimeter (cm) using the exact conversion factor (1 inch = 2.54 centimeter). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Inches to Centimeters converter
Converter
Length Converter
Convert SI, imperial, US customary, astronomical, scientific, and historical length units.
Context values
Some unit families need one extra value for a physically accurate result.
Centimeter is 0.01 meter units.
Result = input x 0.0254 / 0.01.
Length uses the meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Inches to Centimeters
Inch and Centimeter both measure length. Inch is typically associated with united States and United Kingdom (small measurements, screen sizes, hardware), while Centimeter is typically associated with standard small-length unit worldwide except the US.
Formula
centimeters = inches × 2.54
This factor comes from each unit's defined relationship to the category's base unit: 1 inch equals 0.0254 base units, and 1 centimeter equals 0.01 base units, so dividing one by the other gives the direct inch-to-centimeter factor of 2.54.
Simple example
1 in × 2.54 = 2.54 cm
1 inch = 2.54 centimeters.
Real-world example
10 in × 2.54 = 25.4 cm
10 inches = 25.4 centimeters.
Conversion table
| Inch (in) | Centimeter (cm) |
|---|---|
| 1 in | 2.54 cm |
| 5 in | 12.7 cm |
| 10 in | 25.4 cm |
| 21.0975 in | 53.58765 cm |
| 42.195 in | 107.1753 cm |
| 100 in | 254 cm |
Reverse conversion: Centimeter to Inch
2.54 cm × 0.3937007874 = 1 in
2.54 centimeters = 1 inches.
inches = centimeters × 0.393700787402
For a page dedicated to this direction, see Centimeter to Inch.
Inch vs. Centimeter
| Aspect | Inch | Centimeter |
|---|---|---|
| Family | US/imperial customary unit | SI derived (metric prefix) unit |
| Typical use | Screen and display size measurement worldwide (even in metric countries) | Everyday small-object and body measurement (height, clothing sizes) outside the US |
| Where it's used | United States and United Kingdom (small measurements, screen sizes, hardware) | Standard small-length unit worldwide except the US |
Understanding the Inch
Inch (in) measures distance. The international inch is defined as exactly 25.4 millimeters. It is classified as a US/imperial customary unit.
Where it's used: United States and United Kingdom (small measurements, screen sizes, hardware)
Uses of the Inch today
- Screen and display size measurement worldwide (even in metric countries)
- US/UK small-object and body measurement
- Hardware, tools, and pipe fittings (US)
History of the Inch
The inch traces to medieval England, traditionally defined as the length of three barleycorns, later standardized as 1/12 of a foot. The international inch (exactly 25.4 mm) was fixed by the same 1959 agreement that standardized the foot and yard.
Historical origin. Inch was not the invention of a single named person; it developed through the process described above.
Understanding the Centimeter
Centimeter (cm) measures distance. A centimeter is one-hundredth of a meter. It is classified as a SI derived (metric prefix) unit.
Where it's used: Standard small-length unit worldwide except the US
Uses of the Centimeter today
- Everyday small-object and body measurement (height, clothing sizes) outside the US
- Construction and manufacturing tolerances internationally
History of the Centimeter
The centimeter follows directly from the meter via the 'centi-' SI prefix (10⁻²), introduced with the metric system in the 1790s.
Historical origin. Centimeter was not the invention of a single named person; it developed through the process described above.
Inch — sources
- NIST — International yard and pound (1959) — Fixes the modern inch at exactly 25.4 millimeters.
Centimeter — sources
- BIPM SI Brochure — SI prefixes — Defines 'centi-' as the prefix for 10⁻².
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many centimeters are in 1 inch?
1 inch equals 2.54 centimeters, using the exact defined conversion factor rather than an estimate.
How do I convert inch to centimeter?
Multiply the inch value by 2.54. The converter above does this instantly to whatever precision you set.
How do I convert centimeter back to inch?
Use the reverse factor: 1 centimeter equals 0.3937007874 inches. You can also use the swap control in the converter above to flip the direction instantly.
What is a inch?
Inch (in) measures distance. The international inch is defined as exactly 25.4 millimeters. It is classified as a US/imperial customary unit.
What is a centimeter?
Centimeter (cm) measures distance. A centimeter is one-hundredth of a meter. It is classified as a SI derived (metric prefix) unit.
Is the inch to centimeter conversion exact?
Yes. The international inch is defined as exactly 25.4 millimeters. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
Where is the inch still used today?
United States and United Kingdom (small measurements, screen sizes, hardware)