About this tool
Work out a display's pixel density and related figures from its resolution and diagonal size, all in your browser. Enter the horizontal and vertical pixel counts and the diagonal screen size in inches to see PPI, dot pitch, total megapixels and aspect ratio update live.
The diagonal in pixels is √(width² + height²); PPI (pixels per inch) is that diagonal divided by the diagonal size in inches. Dot pitch is 25.4 / PPI millimetres, total megapixels is width × height ÷ 1,000,000, and the aspect ratio reduces width : height by their greatest common divisor. For example 1920 × 1080 on a 24-inch screen gives √(1920² + 1080²) ≈ 2202.9 px, so 2202.9 / 24 ≈ 91.79 PPI, a 16:9 ratio and about 2.07 MP.
Handy for comparing monitors, laptops and phones, or checking if a screen is 'Retina'-sharp at your viewing distance.