# Pixel density: what it is and how it works · Zorraquino
> Pixel density expresses the number of pixels within a physical length, usually in pixels per inch, or PPI.
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# Pixel density

Pixel density expresses the number of pixels within a physical length, usually in pixels per inch, or PPI. It relates resolution to the size of a screen or a reproduced image

What it means, how it is used and where it comes up, with its related concepts.

[The whole glossary](https://www.zorraquino.com/en/dictionary)

## What it is and how it works

It is not the same as a printer's DPI, which describes printed dots. Nor does it determine perceived quality on its own: size, viewing distance and content also matter. Interfaces additionally use logical units to adapt their presentation to screens with different densities.

Also known as

PPI, Pixels per inch

Topics

[Experience and service design](https://www.zorraquino.com/en/dictionary/category/experiencia-y-diseno-de-servicios)

## Related concepts

- [Pixel](https://www.zorraquino.com/en/dictionary/internet/pixel.html)
- [Density-independent pixels (dp)](https://www.zorraquino.com/en/dictionary/ux/dips-or-dp.html)
- [Points (pt)](https://www.zorraquino.com/en/dictionary/internet/points-or-pts.html)