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About Screen Ppi Calculator Online
This tool calculates the pixel density (PPI — pixels per inch) of any display given the diagonal screen size and the resolution. Higher PPI means sharper images and crisper text; lower PPI can leave individual pixels visible up close.
PPI matters when buying monitors, phones, tablets, and laptops. A 15.6" 1920×1080 laptop screen is about 141 PPI; the same resolution on a 24" desktop monitor drops to 92 PPI — visibly less crisp. Smartphones easily exceed 400 PPI thanks to small screens and dense panels.
Use it before buying a display, when comparing two phones or monitors with different sizes and resolutions, or when sourcing panels for a custom build.
How to use this tool
How to compute a display's PPI (pixels per inch)
Pixel resolution
"Width (px)" and "Height (px)" are the screen's native resolution — the panel's actual pixel count (e.g. 1920 × 1080 for a full-HD monitor, 3840 × 2160 for 4K).
Diagonal size
"Diagonal (inches)" is the screen's advertised size — the same number the spec sheet calls 27", 13.3", etc. The tool assumes the resolution fills the whole diagonal.
Press Run
Result returns ppi = sqrt(width² + height²) / diagonal, rounded to 2 decimals. The math: the diagonal pixel count divided by the diagonal inch count.
Reading the number
Below 100 = blocky on a desk monitor. 110–130 = sweet spot for non-retina desktops. 220+ = retina/HiDPI territory; the OS usually scales the UI 2× to keep elements at normal size.