Authoritative definitions of the International System of Units and SI prefixes.
Unit conversion
Pixels per inch to Pixels per centimetre Converter
1 ppi ≈ 0.393700787402 ppcm. Enter a value to convert ppi to ppcm, then use the formula and table below. Displayed digits may be rounded.
Pixel densityInstant result
Decimals
Formula result = input × 1 ÷ 2.54. 1 ppi ≈ 0.3937 ppcm
Nonzero results too small for the selected decimal places use scientific notation.
Nonzero results too small for the selected decimal places use scientific notation.
Common examples
One value, several units
Pixels per centimetre0.3937 ppcm
Dots per inch1 dpi
Dots per centimetre0.3937 dpcm
Conversion table
| ppi | ppcm |
|---|---|
| 1 ppi | 0.3937 ppcm |
| 2 ppi | 0.7874 ppcm |
| 5 ppi | 1.9685 ppcm |
| 10 ppi | 3.937 ppcm |
| 25 ppi | 9.8425 ppcm |
| 50 ppi | 19.685 ppcm |
| 100 ppi | 39.3701 ppcm |
Conversion chart
1 ppi0.3937 ppcm
5 ppi1.9685 ppcm
10 ppi3.937 ppcm
25 ppi9.8425 ppcm
50 ppi19.685 ppcm
Worked example
1 ppi ≈ 0.393700787402 ppcm. Apply the selected conversion formula to other input values.
Unit definition
Pixels per inch (ppi) One pixels per inch equals 1 pixel per inch.
Unit history
Pixels per inch is represented here using its modern SI definition or an internationally accepted relationship to an SI base unit.
Step by step
1. Parse the value, including fractions.
2. Convert ppi to pixel per inch.
3. Convert the base value to ppcm and apply your display precision.
Understand the result before using it
Pixels per inch to Pixels per centimetre converts a value measured in Pixels per inch (ppi) into the equivalent value in Pixels per centimetre (ppcm). The numerical value changes because the size and definition of the selected unit changes; the underlying quantity does not.
Calculated result
The conversion follows the displayed unit relationship. Display rounding can hide additional digits, and measured inputs cannot become more accurate merely by changing units.
Formula, assumptions, and example
Formula
result = input × 1 ÷ 2.54
Assumptions
- Pixels per inch and Pixels per centimetre represent the same pixel density quantity.
- The input is expressed in ppi; the output is expressed in ppcm.
- The unit definitions and conventional relationship shown on this page apply.
Worked example
1 ppi ≈ 0.393700787402 ppcm. For another value, apply the same relationship and round only to the precision your source measurement supports.
When to use it
Good uses
- Read a ppi measurement in a document that expects ppcm.
- Compare a pixels per inch value with a value reported in pixels per centimetre.
- Check the ppi to ppcm arithmetic before copying the result into another calculation.
Limitations
Common mistakes to avoid
- PPI describes pixels in an image or display; printer DPI can describe physical dots and is not always interchangeable.
- Round the output to a precision justified by the original measurement.
- Verify safety-critical, regulated, laboratory, and contractual conversions against the controlling standard.
Sources and further reading
These references explain the underlying standards or provide authoritative context. Your own contract, institution, clinician, product documentation, local code, or governing standard may be the controlling source.
Guidance on unit names, symbols, conversions, and numerical presentation.
Questions about this calculation
How do I convert Pixels per inch to Pixels per centimetre?
result = input × 1 ÷ 2.54. Input is in ppi; result is in ppcm. 1 ppi ≈ 0.393700787402 ppcm. The displayed digits may be rounded.
What is 1 ppi in ppcm?
1 ppi ≈ 0.393700787402 ppcm. The displayed digits may be rounded.
Can I reverse the ppi to ppcm conversion?
Yes. Swap the source and target units in the converter. The reverse relationship converts ppcm back to ppi.
Is the Pixels per inch to Pixels per centimetre result exact?
The conversion follows the displayed unit relationship. Display rounding can hide additional digits, and measured inputs cannot become more accurate merely by changing units.