Authoritative definitions of the International System of Units and SI prefixes.
Dedicated unit pair
Pixels per inch to Dots per inch
Convert ppi to dpi instantly, then review the formula, assumptions, and rounding guidance.
Pixel densityInstant result
Decimals
Formula result = input × 1 ÷ 1. 1 ppi = 1 dpi
Common examples
One value, several units
Pixels per centimetre0.3937 ppcm
Dots per inch1 dpi
Dots per centimetre0.3937 dpcm
Conversion table
| ppi | dpi |
|---|---|
| 1 ppi | 1 dpi |
| 2 ppi | 2 dpi |
| 5 ppi | 5 dpi |
| 10 ppi | 10 dpi |
| 25 ppi | 25 dpi |
| 50 ppi | 50 dpi |
| 100 ppi | 100 dpi |
Conversion chart
1 ppi1 dpi
5 ppi5 dpi
10 ppi10 dpi
25 ppi25 dpi
50 ppi50 dpi
Worked example
96 ppi is approximately 37.795 pixels per centimetre.
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 dpi and apply your display precision.
Understand the result before using it
Pixels per inch to Dots per inch converts a value measured in Pixels per inch (ppi) into the equivalent value in Dots per inch (dpi). 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 ÷ 1
Assumptions
- Pixels per inch and Dots per inch represent the same pixel density quantity.
- The input is expressed in ppi; the output is expressed in dpi.
- The unit definitions and conventional relationship shown on this page apply.
Worked example
1 ppi = 1 dpi. 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 dpi.
- Compare a pixels per inch value with a value reported in dots per inch.
- Check the ppi-to-dpi 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 Dots per inch?
result = input × 1 ÷ 1 Using the displayed relationship, 1 ppi equals 1 dpi.
How many Dots per inch are in one Pixels per inch?
One Pixels per inch is 1 Dots per inch. The displayed digits may be rounded.
Can I reverse the ppi to dpi conversion?
Yes. Swap the source and target units in the converter. The reverse relationship converts dpi back to ppi.
Is the Pixels per inch to Dots per inch 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.