Screen PPI Calculator (Pixel Density)
By Santaji GadepatilinUpdated October 27, 2026
Pixel density (PPI) measures how sharp a screen looks. It depends on the resolution and screen size. This free screen PPI calculator solves for whichever value you leave blank and shows the formula and steps.
How to use the screen PPI calculator
Enter the screen’s resolution and diagonal. Pixel density and dot pitch are calculated.
Screen PPI formula
PPI = √(w² + h²) ÷ diagonal
Common screens
| Screen | PPI |
|---|---|
| 24″ 1080p | 91.8 |
| 27″ 1440p | 108.8 |
| 27″ 4K | 163.2 |
| 32″ 4K | 137.7 |
| 6.1″ 2532 × 1170 phone | 457.5 |
Pixel density of common screens
| Screen | Resolution | Size | PPI |
|---|---|---|---|
| Full HD monitor | 1920 × 1080 | 24″ | 92 |
| QHD monitor | 2560 × 1440 | 27″ | 109 |
| 4K monitor | 3840 × 2160 | 27″ | 163 |
| 4K monitor | 3840 × 2160 | 32″ | 138 |
| Laptop FHD | 1920 × 1080 | 15.6″ | 141 |
| Laptop QHD+ | 2560 × 1600 | 14″ | 216 |
| Phone FHD+ | 2400 × 1080 | 6.5″ | 405 |
| 4K TV | 3840 × 2160 | 55″ | 80 |
When is PPI “enough”?
Whether you can see individual pixels depends on viewing distance:
| Viewing distance | PPI where pixels become hard to see (20/20 vision) |
|---|---|
| 25–30 cm (phone) | about 300 |
| 50–60 cm (laptop) | about 150 |
| 60–80 cm (desktop monitor) | about 110–140 |
| 2.5 m (TV) | about 35 |
This is why a 55-inch 4K TV at 80 PPI looks sharp from the sofa.
Scaling
High-PPI screens usually run with display scaling (for example 150%) so text stays readable. A 27-inch 4K monitor at 150% gives the same workspace as a 1440p monitor but with sharper text.
Frequently asked questions
How is PPI calculated?
PPI = √(width² + height²) ÷ diagonal in inches.
What PPI looks sharp?
For a desktop monitor viewed at arm's length, about 110 PPI and above looks sharp; phones held closer often exceed 400 PPI.
What is dot pitch?
The distance between pixels — the reciprocal of PPI.
What is the PPI of a 27-inch 1440p monitor?
About 109 PPI.
Is higher PPI always better?
Only up to the point where your eyes cannot see individual pixels at your viewing distance.