Display pixel density
Enter a display’s pixel resolution and physical diagonal to find its PPI, pixel pitch, aspect ratio, active dimensions, and area.
—pixels per inch
Browser zoom and operating-system scaling do not change a display’s physical PPI.
FORMULA
PPI = √(horizontal pixels² + vertical pixels²) ÷ physical diagonal in inches. For a 2560 × 1440 display with a 27-inch diagonal, that equals approximately 108.8 PPI.
This is an objective physical screen measurement. It is independent of an image file’s print-resolution tag or printer ink droplets.
MONITOR BENCHMARK TABLE
Every value below is calculated with the same formula the calculator uses. Labels describe generic form factors and common resolutions, not specific models — verify your own display’s exact panel specifications with its manufacturer.
| Device / Form Factor | Native Resolution | Diagonal | Pixel Density | Pixel Pitch |
|---|---|---|---|---|
| 24″ Full HD Monitor | 1920 × 1080 (16:9) | 24.0 in | 91.8 PPI | 0.2767 mm |
| 27″ QHD / 1440p Monitor | 2560 × 1440 (16:9) | 27.0 in | 108.8 PPI | 0.2335 mm |
| 27″ 4K UHD Monitor | 3840 × 2160 (16:9) | 27.0 in | 163.2 PPI | 0.1557 mm |
| 32″ 4K UHD Monitor | 3840 × 2160 (16:9) | 32.0 in | 137.7 PPI | 0.1845 mm |
| 15.6″ Full HD Laptop Example | 1920 × 1080 (16:9) | 15.6 in | 141.2 PPI | 0.1799 mm |
| 14″ Laptop Example (16:10) | 1920 × 1200 (8:5) | 14.0 in | 161.7 PPI | 0.1571 mm |
| 27″ 5K Desktop Display Example | 5120 × 2880 (16:9) | 27.0 in | 217.6 PPI | 0.1167 mm |
| 34″ Ultrawide QHD Example | 3440 × 1440 (21.5:9) | 34.0 in | 109.7 PPI | 0.2316 mm |
| 10.9″ Tablet Example | 2360 × 1640 (about 1.44:1) | 10.9 in | 263.7 PPI | 0.0963 mm |
| 6.1″ Smartphone Example | 2532 × 1170 (about 19.5:9) | 6.1 in | 457.3 PPI | 0.0555 mm |
| 6.7″ Smartphone Example | 2796 × 1290 (about 19.5:9) | 6.7 in | 459.6 PPI | 0.0553 mm |
| 55″ 4K TV Example | 3840 × 2160 (16:9) | 55.0 in | 80.1 PPI | 0.3171 mm |
DISPLAY PPI FAQ
Screen PPI is calculated using the Pythagorean theorem. Formula: Diagonal Pixels = √(Width_px² + Height_px²), then PPI = Diagonal Pixels ÷ Diagonal Inches. For a 27" 2560 × 1440 display, diagonal pixels equal 2937.3, giving 108.8 PPI.
Pixel pitch is the distance between the centers of two adjacent pixels, measured in millimeters. Formula: Pixel Pitch (mm) = 25.4 ÷ PPI. A higher PPI corresponds to a smaller pixel pitch and a sharper image.
Retina is an Apple marketing name, not one universal PPI threshold. Whether pixels are noticeable depends on viewing distance, eyesight, content, and display characteristics. For a one-arcminute visual-acuity estimate, divide about 3438 by viewing distance in inches: roughly 344 PPI at 10 inches or 172 PPI at 20 inches. These are estimates, not a certification for any display.
No. Operating system display scaling changes the size of user interface elements, fonts, and virtual pixels, but the physical pixel density of the monitor hardware remains constant.
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