How to use this calculator
Enter the monitor diagonal size and the horizontal and vertical resolution. You can use a preset for common 1080p, 1440p, 4K, 5K, ultrawide, and dual-QHD displays, or enter a custom resolution.
The result shows pixels per inch, pixel pitch, total pixels, and a practical sharpness label. Smaller pixel pitch means pixels are packed more tightly, which usually makes text and fine UI details look cleaner.
If you are comparing TVs instead of desktop monitors, use the TV Resolution Calculator. For projector screen planning, use the Projector Screen Size Calculator.
Monitor PPI formula
diagonal pixels = sqrt(horizontal pixels^2 + vertical pixels^2)PPI = diagonal pixels / screen diagonal inchespixel pitch (mm) = 25.4 / PPIPPI uses the pixel diagonal and the physical display diagonal. This is why a 27-inch 4K monitor is much denser than a 32-inch 4K monitor, even though both have the same number of pixels.
Assumptions and methodology
This calculator treats the advertised monitor size as the visible diagonal and uses the native panel resolution. It estimates physical pixel density, not operating system scaling, subpixel layout, panel quality, text rendering, or eyesight differences.
- PPI is calculated from diagonal pixels and diagonal inches.
- Pixel pitch is the physical size of one pixel in millimeters.
- The 20/20 visibility distance uses one arcminute as a simplified visual acuity threshold.
- Real perceived sharpness also depends on viewing distance, anti-glare coating, panel type, scaling, and text rendering.
PPI is useful for comparing displays before buying, but it should be read together with viewing distance. A 27-inch 4K monitor has a higher PPI than a 32-inch 4K monitor, yet the larger screen may still feel comfortable if you sit farther back or prefer larger UI scaling.
Example calculations
27-inch 1440p monitor
A 27-inch 2,560 x 1,440monitor has about 108.8 PPI, a pixel pitch of 0.233 mm, and 3.69 million pixels. At typical desk distance, this is a comfortable standard density for work, gaming, and general desktop use.
Monitor PPI chart
This chart compares common monitor size and resolution combinations. Use the calculator above for exact custom display sizes.
| Size | Resolution | PPI | Pixel pitch | Density |
|---|---|---|---|---|
| 24 in | 1920 x 1080 | 91.8 | 0.277 mm | Comfortable standard |
| 24 in | 2560 x 1440 | 122.4 | 0.208 mm | Sharp |
| 27 in | 1920 x 1080 | 81.6 | 0.311 mm | Soft |
| 27 in | 2560 x 1440 | 108.8 | 0.233 mm | Comfortable standard |
| 27 in | 3840 x 2160 | 163.2 | 0.156 mm | Very sharp |
| 32 in | 2560 x 1440 | 91.8 | 0.277 mm | Comfortable standard |
| 32 in | 3840 x 2160 | 137.7 | 0.184 mm | Sharp |
| 34 in | 3440 x 1440 | 109.7 | 0.232 mm | Comfortable standard |
| 40 in | 5120 x 2160 | 138.9 | 0.183 mm | Sharp |
Popular monitor PPI questions
These quick answer pages cover common monitor sharpness searches, such as 27-inch 1440p, 32-inch 4K, 24-inch 1080p, and 34-inch ultrawide pixel density.
Related calculators
TV Dimensions Calculator
Convert diagonal TV size into approximate screen width and height.
TV Resolution Calculator
Compare 1080p, 4K, and 8K detail based on TV size, viewing distance, and visual acuity.
Projector Screen Size Calculator
Estimate screen size from projector distance and throw ratio.
Projector Brightness Calculator
Estimate recommended projector brightness from screen size and room light.
FAQ
How do I calculate monitor PPI?
Calculate the diagonal pixel count with the Pythagorean theorem, then divide it by the screen diagonal in inches. For example, a 2560 x 1440 display has about 2938 diagonal pixels; divided by 27 inches, that is about 108.8 PPI.
What is a good PPI for a monitor?
Around 90-110 PPI is common for standard desktop monitors, 110-145 PPI feels sharper for many users, and 145+ PPI is very sharp but often benefits from operating system scaling.
Is 27-inch 1440p a good monitor density?
Yes. A 27-inch 2560 x 1440 monitor is about 108.8 PPI, which is a comfortable and popular density for office work, gaming, and general desktop use.
Is 32-inch 4K sharper than 27-inch 1440p?
Yes. A 32-inch 3840 x 2160 monitor is about 137.7 PPI, while a 27-inch 2560 x 1440 monitor is about 108.8 PPI. The 32-inch 4K option has smaller pixels and usually looks sharper.
Is PPI the same as resolution?
No. Resolution is the number of pixels, such as 1920 x 1080 or 3840 x 2160. PPI also includes physical screen size, so the same resolution can look sharper on a smaller screen and softer on a larger one.
Does viewing distance affect how sharp a monitor looks?
Yes. Higher PPI helps most at close desk distances. As viewing distance increases, individual pixels become harder to see, so a lower PPI can still look acceptable from farther away.