PPI Calculator
Work out the pixel density of any screen from its resolution and diagonal size, plus the asset multiplier you need for retina displays.
Scan to open on your phone
Point your phone camera at the code to open this tool.
Work out the pixel density of any screen from its resolution and diagonal size, plus the asset multiplier you need for retina displays.
How to use PPI Calculator
- Open the toolNo signup and nothing to install; it works as soon as the page loads.
- Set “Width (px)”
- Set “Height (px)”
- Set “Diagonal (inches)”
- Read the resultChange any input and the result is recalculated immediately.
Worked example with the defaults
- PIXEL DENSITY · 2560 × 1440 on a 27" screen
- 108.8 PPI
Nothing you enter leaves your device
All of the work happens inside your browser. Whatever you type is never packaged up and sent to a server, and no request this page makes carries it.
That makes it safe for contract amounts, personal details and internal documents you would rather not hand to a third party — close the tab and it is gone.
What this tool does not do
PPI Calculator only does what a browser can do on its own — it talks to no backend service. So it keeps no history for you and syncs nothing across devices; if you need a record, copy or download the result.
It is also not a substitute for professional judgement. For legal, medical or tax decisions, treat the output as a starting point rather than a final answer.
Frequently Asked Questions
- What is the difference between PPI and DPI?
- PPI describes screen pixel density, while DPI describes printer output resolution. Screens are measured in PPI even though the terms are often used interchangeably.
- How is PPI calculated?
- PPI equals the diagonal resolution in pixels divided by the diagonal size in inches. The diagonal pixel count comes from the Pythagorean theorem.