Screen PPI calculator
Work out a screen's pixel density (PPI) from its resolution and diagonal size — higher PPI generally means a sharper-looking image at normal viewing distance.
Result
Pixel density
How to use this calculator
- Enter the screen's horizontal and vertical resolution in pixels.
- Enter the screen's diagonal size in inches.
- Read the pixel density.
Assumptions
- Treats the panel as a perfect rectangle — this is standard for essentially all screens.
Technical details: what the fields mean
- Horizontal resolution
widthPx - Horizontal resolution in pixels, e.g. 1920 for a 1080p screen.
- Vertical resolution
heightPx - Vertical resolution in pixels, e.g. 1080 for a 1080p screen.
- Screen diagonal
diagonalInches - Screen size measured diagonally, in inches — the number usually quoted in a spec sheet (e.g. '27-inch monitor').
Methodology
Diagonal resolution (px) = √(width² + height²). PPI = diagonal resolution ÷ diagonal size in inches.
Worked example
1920×1080, 24-inch screen
Inputs: widthPx=1920, heightPx=1080, diagonalInches=24
Result: 92 PPI
Practical guidance
- A higher PPI at a given viewing distance looks sharper — smartphones typically run 400+ PPI since they're viewed close up, while a large TV viewed from across a room can look sharp at well under 100 PPI.
Common mistakes
- Comparing PPI across very different screen types (phone vs TV) without considering typical viewing distance — PPI alone doesn't determine perceived sharpness.
FAQs
What is a 1920x1080 24-inch monitor's PPI?
About 92 PPI.