Calculate pixels per inch (PPI) for displays or dots per inch (DPI) for printing based on resolution and size.
| Device | Resolution | Size | PPI |
|---|---|---|---|
| iPhone 15 | 2556×1179 | 6.1" | 460 |
| MacBook Air M2 | 2560×1664 | 13.6" | 224 |
| 4K Monitor | 3840×2160 | 27" | 163 |
| 1080p Monitor | 1920×1080 | 24" | 92 |
PPI (pixels per inch) measures screen pixel density. DPI (dots per inch) measures print dot density. They are often used interchangeably, but technically PPI is for screens and DPI for printers.
Apple defines Retina as when individual pixels are indistinguishable at normal viewing distance. For phones this is ~300+ PPI; for laptops ~220+ PPI; for monitors ~200+ PPI.
Enter any two of: print dimensions, pixel dimensions, or DPI/PPI. The calculator solves for the third value and recommends resolution for various use cases.
DPI = Pixels / Print Size (inches). Pixels = DPI Γ Print Size. Print Size = Pixels / DPI.
A 4000Γ3000 pixel photo printed at 300 DPI: 4000/300 = 13.3" Γ 10" print. At 72 DPI (screen): 55.6" Γ 41.7" β much larger but lower quality.
Use 300 DPI for high-quality prints, 150 DPI for acceptable prints, 72 DPI for web/screen. Upscaling a low-res image does not add real detail. Always shoot/design at the highest resolution needed.