Formula
An inch is 25.4 millimetres:
PPI = 25.4 / pitch in mm
The screen PPI page uses a pixel resolution and a diagonal. This page uses the spacing of one dot.
Assumptions
- The pitch is the centre-to-centre distance of adjacent pixels.
- The inch is the international inch of 25.4 mm.
- Pixels are square.
Worked example
A 0.25 mm dot pitch is 101.6 PPI.
Input definitions
- Dot pitch
- The distance from the centre of one pixel to the centre of the next, in millimetres.
- PPI
- How many of those pitches fit in one inch.
Limitations
This is a planning figure from the numbers you type. It is not a measurement of a network, a camera, a printer, or a power supply.
Questions
Why is 0.25 mm equal to 101.6 PPI?
25.4 divided by 0.25 is 101.6. A smaller pitch is a denser screen.
Where do I use resolution instead?
On the screen PPI page, which takes pixel width, pixel height, and the diagonal in inches.