Screen size and PPI calculator
PPI and physical size from the diagonal and resolution, a to-scale comparison of two screens, and a viewing-distance guideline.
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How to use
- Enter the diagonal in inches and the resolution (width and height in pixels).
- Read PPI, physical width and height, and pixel pitch.
- Press “Compare two screens” to enter a second monitor; they are drawn at the same scale.
- The viewing distance is a guideline range, not a rule.
Worked example
Example: 27 in at 2560×1440 → √(2560²+1440²) = 2937.3 px ÷ 27 in = 108.8 PPI; about 59.8 × 33.6 cm. 24 in at 1920×1080 is 91.8 PPI, about 53.1 × 29.9 cm.
Limits
- The diagonal is the maker’s nominal viewable size; real panels can differ slightly, and curved screens are measured along the curve.
- The viewing distance (1.0–1.5× the diagonal) is a common rule of thumb. The pixel distance (1 arcminute) is a reference for typical eyesight. Preference and use change the best distance.
- Higher PPI is not automatically better; scaling settings in the OS change how big things look.
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