Screen Resolution & DPI Calculator
Work out pixel density (PPI/DPI), aspect ratio, dot pitch and total megapixels for any screen — and see how sharp a display really is before you buy.
What PPI and DPI actually mean
PPI (pixels per inch) describes how tightly packed the dots are on a screen. The higher the number, the sharper the image and the less you can see individual pixels. The term DPI (dots per inch) means the same thing for displays in everyday use, though strictly DPI belongs to printing. This calculator works out the PPI from your resolution and physical screen size, along with the aspect ratio, total megapixels and dot pitch.
Two screens with the same resolution can look very different. A 1080p picture spread across a 32-inch TV has far lower PPI — and visibly chunkier pixels — than the same 1080p packed into a 6-inch phone. That is why phones look razor-sharp while large budget monitors can appear coarse at the same resolution.
How much PPI do you need?
| Device & distance | Comfortable PPI | Notes |
|---|---|---|
| Phone (held ~30 cm) | 300–500 | Close viewing demands the highest density |
| Laptop / monitor (arm’s length) | 110–220 | 140+ looks crisp; 200+ is “Retina-class” |
| TV (2–3 m away) | 30–80 | Distance hides low density, so 4K shines on big sets |
Buying a monitor or phone? PPI is one of the clearest specs to judge sharpness once you know the size and resolution. Our laptop buying guide and smartphone buying guide put it in context alongside panel type, refresh rate and brightness.
Frequently asked questions
What is the difference between PPI and DPI?
For screens they are used interchangeably to mean pixel density. Strictly, PPI (pixels per inch) refers to displays and DPI (dots per inch) to printing, but in everyday tech talk DPI and PPI describe the same screen sharpness.
How do I calculate PPI?
Take the diagonal in pixels — the square root of (width² + height²) — and divide by the screen's diagonal size in inches. For 1920×1080 on a 24-inch screen that is about 92 PPI. This calculator does it instantly for any resolution and size.
What PPI counts as a Retina or sharp display?
There is no single threshold because it depends on viewing distance, but roughly 200+ PPI on a laptop or monitor and 300+ PPI on a phone are considered very sharp, where individual pixels are hard to see at normal distance.
Why does my 4K TV not look as sharp as my phone?
Because the pixels are spread over a far larger area, giving much lower PPI. A 4K 55-inch TV is around 80 PPI versus 400+ on a phone. You sit much further from a TV, though, so it still looks crisp in practice.
What is dot pitch?
Dot pitch is the physical distance between pixel centres, usually in millimetres — essentially the inverse of PPI. A smaller dot pitch means a denser, sharper screen. This tool shows it alongside PPI.
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