Screen PPI & Size Calculator
Pixel density, physical dimensions and dot pitch from diagonal size and resolution — compare monitors before buying.
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What PPI Tells You
PPI = √(width² + height²) ÷ diagonal inches: a 27-inch 2560×1440 monitor lands at 109 PPI — the sweet spot where text renders sharp at 100% scaling. The same panel size at 4K jumps to 163 PPI (needs ~150% scaling); a 24-inch 1080p sits at 92 PPI, visibly coarser. The tool also gives physical width/height (does it fit the desk?) and dot pitch in mm.
Buying bands: 90-110 PPI is comfortable for desktops at 100% scaling; 140-160+ targets HiDPI/Retina-style rendering at 150-200%; phones run 350-550 PPI because they sit much closer to the eye. Viewing distance is the missing variable — a 55-inch 4K TV at 3 m looks sharper than a 27-inch 1440p at 60 cm.
Frequently Asked Questions
Is higher PPI always better?
Past what your eye resolves at your viewing distance, no — you pay in GPU load and scaling quirks. At 60-70 cm desk distance, gains fade above ~200 PPI.
Why does Windows text look blurry on my new 4K monitor?
Fractional scaling (125/150%) blurs apps that are not DPI-aware. Integer scaling (200%) or apps updated for per-monitor DPI fix it — a reason some buyers prefer ~110 PPI panels at 100%.
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Screen PPI & Size Calculator