acalculator

How do I convert inches to cm?

Type either value and the other one updates as you type.

Your numbers

Centimeters (cm)
2.54

1 in = 2.54 cm.

Centimeters (cm): 2.54. 1 in = 2.54 cm.

Centimeters (cm) by inches (in)

How to calculate

Converts inches (in) to centimeters (cm) and back, with the exact unit definitions.

Example with the default inputs (Inches (in) 1): 1 in = 2.54 cm.

Formula: cm = in × 2.54

  • 1 inch = 2.54 centimeters, from the exact definitions in NIST SP 811.
  • The answer shows at most 6 decimal places; the calculation keeps full precision.

Machine-readable copies: Markdown, JSON.

Worked examples

Each example is checked against the calculator on every build.

  1. Inches (in) 1 gives Centimeters (cm) 2.54.Source: exact unit definitions in NIST SP 811 (2008), Appendix B.8
  2. Inches (in) 12 gives Centimeters (cm) 30.48.Source: exact unit definitions in NIST SP 811 (2008), Appendix B.8
  3. Centimeters (cm) 30.48 gives Inches (in) 12.Source: exact unit definitions in NIST SP 811 (2008), Appendix B.8

Other questions people ask

How many centimeters are in an inch?

1 inch is 2.54 centimeters, from the exact unit definitions (NIST SP 811).

How do I convert inches to cm?

Multiply by 2.54: cm = in × 2.54. For example, 1 in × 2.54 = 2.54 cm.

How do I convert cm back to inches?

Multiply by 0.393701, or type the centimeters into the second box and the converter works it out. 1 centimeter is 0.393701 inches.