PPI Calculator
Enter horizontal and vertical resolution plus diagonal inches to get PPI, dot pitch, total pixels and the matching density tier — or tap a preset to load common device specs instantly.
How to read it
- Judge PPI against viewing distance, not in isolation: ~100–140 is fine at 70cm desk distance, phones at 30cm want 300+, TVs at 2–3m only need 50–80.
- Retina distance estimates when individual pixels stop being resolvable (1 arcminute acuity) — beyond it, raising PPI brings little visible gain.
- High PPI pairs with OS scaling: 27″ 4K at 163 PPI usually runs 150%, laying out like 1440p while drawing text at full 4K sharpness.
Frequently asked questions
How much PPI is enough?
It depends on viewing distance: 100–140 PPI is fine at a 70cm desk distance and 160+ is crisp; a phone at 30cm wants 300+ to hide pixels; a TV at 2–3m only needs 50–80.
How does PPI relate to OS scaling?
High-PPI panels need interface scaling: logical resolution = physical ÷ scale factor. A 27in 4K (163 PPI) typically runs 150% scaling, drawing at 4K physical pixels while laying out like 1440p.
Why is 1440p much pricier than 1080p at the same size?
Doubling pixels raises demands on backlight uniformity, driver ICs and yield — and premium panels usually bundle higher refresh, wider gamut and deeper bit depth. PPI measures density only, not brightness, contrast or color quality.
What is retina viewing distance?
The estimated minimum distance at which individual pixels stop being resolvable, based on 1-arcminute acuity: the higher the PPI, the closer you can sit. It's an estimate — contrast, font rendering and eyesight all shift the perception.