Monitor PPI Calculator
Same Resolution, Different Sharpness
A 1920x1080 panel looks noticeably sharper on a 24-inch monitor than on a 32-inch one, even though both display the exact same number of pixels. What changes is pixel density — how tightly those pixels are packed into the physical screen — and that density, measured in pixels per inch, is what actually determines how crisp text and images appear at a normal viewing distance.
The Formula
The diagonal pixel count is found with the Pythagorean theorem from the horizontal and vertical resolution, then divided by the physical diagonal screen size (converted to inches if entered in centimeters) to get pixels per inch.
Where PPI Matters
- Choosing between monitor sizes — deciding whether to scale up to a 32-inch panel at the same resolution as a 27-inch one, understanding that doing so lowers PPI and makes the display noticeably less sharp.
- Matching resolution to screen size — picking a resolution that keeps PPI in a comfortable range for the intended viewing distance, rather than assuming "higher resolution" is always better on every size.
- Design and photo work — PPI affects how accurately a display represents fine detail, which matters for photo editing, typography, and any pixel-precise creative work.
- Comparing laptop and desktop panels — laptop screens are viewed closer than desktop monitors, so a useful PPI for one context can look different for the other; running the numbers puts that comparison on common ground.
PPI Across Common Display Configurations
| Resolution | Screen Size | PPI |
|---|---|---|
| 1366 x 768 | 15.6 in (laptop) | 100.45 |
| 1920 x 1080 | 24 in | 91.79 |
| 1920 x 1080 | 27 in | 81.59 |
| 2560 x 1440 | 27 in | 108.79 |
| 3840 x 2160 | 27 in | 163.18 |
| 3840 x 2160 | 32 in | 137.68 |
Notice the same 1920x1080 resolution drops from 91.79 PPI at 24 inches to 81.59 PPI at 27 inches — identical pixel count, meaningfully different sharpness.
How to Use This Calculator
- Enter the Horizontal Resolution (px).
- Enter the Vertical Resolution (px).
- Enter the Diagonal Screen Size and choose the unit (inches or centimeters).
- Select Calculate to get the pixel density in PPI, along with the resolution's total megapixel count.
Related Calculations
Working out the aspect ratio of a given resolution? Use the Aspect Ratio Calculator, or convert between screen size measurements with the Screen Size Calculator.