Screen Resolution, PPI & Aspect Ratio Calculator
Calculate pixels per inch (PPI), aspect ratio, and total pixel count from screen resolution and size.
Understanding PPI (Pixels Per Inch)
PPI measures pixel density — higher PPI means sharper text and images. Under 100 PPI: Visible pixels at normal viewing distance (older monitors). 100-150 PPI: Standard desktop monitors. 200+ PPI: "Retina" quality — individual pixels invisible at normal distance (modern phones, MacBooks). A 27" 4K monitor has 163 PPI; a 6.1" iPhone has 460 PPI. Mobile screens need higher PPI because you hold them closer.
Common Resolutions
1920×1080 (1080p): Full HD — still the most common gaming and office resolution. 2560×1440 (1440p/QHD): The productivity sweet spot — 78% more pixels than 1080p. 3840×2160 (4K): Four times the pixels of 1080p — ideal for large screens (32"+). 3440×1440 (Ultrawide): 21:9 aspect ratio, popular for gaming and multi-window productivity.
The human eye can perceive approximately 300 PPI at 12 inches viewing distance — this is why Apple chose 326 PPI for the original Retina iPhone. At typical desktop viewing distances (24-30 inches), the equivalent is about 100-120 PPI. Buying a 5K monitor for a desktop you sit 3 feet from provides diminishing returns beyond bragging rights.
