Conversion Methodology
Inch is CM converts every supported length through meters using defined SI and international conversion factors. The defined factors are used without intentional pre-rounding; formatting is applied only when a result is displayed.
Last reviewed: July 2026
Length conversion factors
| Unit | Meter relationship | Status |
|---|---|---|
| Millimeter (mm) | 0.001 meter | Exact SI prefix relationship |
| Centimeter (cm) | 0.01 meter | Exact SI prefix relationship |
| Meter (m) | SI base unit of length | Defined through the speed of light |
| Kilometer (km) | 1,000 meters | Exact SI prefix relationship |
| Inch (in) | 0.0254 meter | Exact international definition |
| Foot (ft) | 0.3048 meter | Exactly 12 international inches |
| Yard (yd) | 0.9144 meter | Exactly 3 international feet |
| Mile (mi) | 1,609.344 meters | Exactly 5,280 international feet |
How conversions are calculated
The converter first changes the source value to meters, then changes meters to the selected target unit.
For the site's primary conversion, one inch is exactly 0.0254 meter and one centimeter is exactly 0.01 meter, so one inch equals exactly 2.54 centimeters.
Rounding and displayed precision
The main converter calculates with the underlying numeric value and normally displays up to eight decimal places. Exact conversion pages use shorter results where practical, and reverse centimeter-to-inch pages generally show up to four decimal places. A displayed rounded value is marked with an approximation sign or described as rounded when the exact decimal does not terminate within the displayed precision.
Screen width and height
Screen size is a diagonal. For an aspect ratio of width w to height h, the visible panel dimensions are estimated with the Pythagorean theorem. Bezels, stands, and device casings are excluded.
height = diagonal × h ÷ √(w² + h²)
Authoritative references
Use the tools
Try the multi-unit length converter, the height converter, or the screen size converter.