Length converter
Inches to centimeters.
Translate inch measurements into centimeters, including mixed fractions from a tape measure.
The marker shows the fractional part of one inch. This diagram illustrates tick positions; it is not a physical-size ruler.
Conversion formula
centimeters = inches × 2.54
Enter the source length above. The result updates immediately. These calculations use exact length definitions: 1 m = 100 cm = 1000 mm, 1 in = 25.4 mm, and 1 ft = 12 in. Only the displayed answer and fractional ruler mark are rounded. The feet-and-inches output splits a length into whole feet and remaining inches; decimal feet do not encode an inch count.
Worked example
12 inches equals exactly 30.48 cm. A 30 cm ruler is therefore slightly shorter than a 12-inch ruler: the difference is 0.48 cm, or 4.8 mm. They are convenient everyday approximations, but they are not the same length.
Conversion table: in → cm
Select a source value to load it into the calculator. Decimal results are displayed to at most six places; inch fractions in this table are rounded to 1/16 inch.
| Inches (in) | Centimeters (cm) | Nearest inch fraction |
|---|---|---|
| 0.635 | ≈ 1/4 in | |
| 1.27 | ≈ 1/2 in | |
| 2.54 | ≈ 1 in | |
| 5.08 | ≈ 2 in | |
| 7.62 | ≈ 3 in | |
| 10.16 | ≈ 4 in | |
| 12.7 | ≈ 5 in | |
| 15.24 | ≈ 6 in | |
| 20.32 | ≈ 8 in | |
| 25.4 | ≈ 10 in | |
| 30.48 | ≈ 12 in | |
| 60.96 | ≈ 24 in |
When to use this conversion
Use this for paper, prints, craft templates, furniture drawings, and dimensions supplied in inches. A screen cannot necessarily display the entire converted length at once, but the numerical conversion is independent of screen size.
For an inch reading between two ticks, record the observed fraction before converting. Converting an uncertain reading into many decimals does not remove measurement uncertainty.
Exact conversion versus a ruler reading
The unit relationship is exact, but a measured object may have uncertainty. At 1/16 inch, the maximum rounding difference is half a tick: 1/32 inch, or 0.79375 mm. The calculator shows the actual rounding difference for your value. Use a finer division only if the source measurement and physical instrument support that precision.
Next steps
Numerical conversion needs no display calibration. Comparing a physical object against your screen does. Use the ruler for small objects, a verified paper ruler away from your display, or an appropriate calibrated instrument for safety-critical measurements.
Related converters
Reference: NIST unit conversion factors. Calculations use the international foot, not historical survey-foot units. Fractions are explicitly approximate. NIST ↗