PPI Calculator
Work out a screen’s pixel density, physical size and the distance pixels disappear at.
Density Alone Does Not Mean Sharp
A phone at 460 pixels per inch and a television at 80 can look equally sharp, because you hold one at 30 centimetres and watch the other from three metres. What decides whether you can see pixels is the angle each one covers at your eye, and that depends on distance just as much as on density.
This works out the density from the resolution and the diagonal, gives you the panel's real physical dimensions and its aspect ratio in lowest terms, and then answers the question that actually matters: how far away does this screen have to be before its pixels stop being resolvable.
Key features
- Density, physical size and aspect ratio — all three from a resolution and a diagonal.
- Inches or centimetres — screens are sold in both.
- Common presets — phones, tablets, laptops, monitors and televisions, to start from or compare against.
- Viewing distance for three levels of eyesight — because acuity is not one number.
- A plain verdict — what the density means in practice at that size.
This tool runs entirely inside your browser using native Web APIs. Your files and text are never uploaded to a server, never logged and never shared with third parties.
How to use: PPI Calculator
- Pick a preset or type your own
Resolution in pixels and the diagonal as the manufacturer quotes it. - Read the density
Pixels per inch, with the panel's real width and height alongside. - Check the aspect ratio
Shown in lowest terms — 16:9, 16:10, 3:2 and so on. - Look at the distances
Past the listed distance, individual pixels are no longer resolvable.
Technical specifications
| Processing location | Entirely in your browser — no server round trip |
|---|---|
| Data uploaded | None. Files and text never leave your device |
| Price | Free — no account, no trial, no usage cap |
| Category | Calculators |
| Works offline | Yes, once the page has loaded |
| Browser support | Chrome 90+, Edge 90+, Firefox 90+, Safari 15+ |
| Interface languages | English, 中文, हिन्दी, Español, العربية |
Frequently asked questions
What counts as a retina display?
It is a marketing term, not a measurement. The underlying claim is that pixels are not individually resolvable at the intended viewing distance — roughly 300 PPI for a phone held at 30 cm, but only about 220 for a laptop at arm's length and far less for a television. A single PPI threshold cannot capture it, which is why the distances here are more useful than the number.
Is PPI the same as DPI?
They are used interchangeably and mean different things. PPI is pixels per inch on a screen; DPI is dots per inch that a printer puts on paper, and printers use several dots to make one perceived colour. For screens, PPI is the correct term.
Why does my 4K monitor need scaling?
Because at 27 inches, 3840×2160 is about 163 PPI — interface elements drawn at their pixel sizes come out roughly half as large as on a traditional 96 PPI display. Operating systems scale to compensate, typically at 150% or 200%. It is not a fault; it is the price of the extra detail.
What is the ideal distance from a monitor?
Far enough that you cannot pick out pixels and close enough to read comfortably — for most desk monitors, somewhere between 50 and 80 centimetres. The distances here give the lower bound from the pixels' point of view; comfort and text size decide the rest.
Does higher PPI use more battery?
Yes, on a phone or laptop. More pixels means more work for the graphics hardware and usually a brighter backlight to push light through a finer pixel structure. It is one reason some phones let you drop the rendering resolution, and why the saving is noticeable.