Enter a resolution and a diagonal screen size to get pixel density in PPI, the dot pitch in millimetres, the aspect ratio and the physical width and height of the panel.
All maths runs locally in your browser.
Phones, tablets, laptops, monitors and TVs — enter any resolution and diagonal.
Dot pitch, aspect ratio and the real width and height of the display in inches and centimetres.
One tap loads common panels like 1080p 24″, 4K 27″ or a 6.1″ phone screen.
Pixel density describes how tightly packed a screen's pixels are. You only need three numbers to work it out.
Screen manufacturers advertise a resolution and a diagonal size, but neither number alone tells you how sharp a display will look. Pixel density ties them together: it is the number of pixels packed into each inch of panel. Two screens with the same 4K resolution can feel completely different if one is a 15-inch laptop and the other is a 65-inch television.
Density decides whether individual pixels are visible at your normal viewing distance, and it drives how operating systems pick their UI scaling factor.
A phone held 30 cm away needs far more density than a TV across the room. Judge a panel by density and distance together, never by density alone.
Older monitor specs quoted dot pitch instead of PPI. It is the same information inverted — the physical gap between pixel centres.
The calculator simplifies the raw resolution into its lowest terms, so 2560 x 1080 is reported as the 64:27 ultrawide ratio.
Answers about pixel density, dot pitch and how sharp a display really is.
Desktop monitors viewed at arm's length look sharp from roughly 110 PPI upward. A 27-inch 1440p panel is about 109 PPI, a 27-inch 4K panel is about 163 PPI, and anything above 200 PPI on a desktop is effectively invisible pixel structure.
Take the square root of the horizontal pixels squared plus the vertical pixels squared to get the diagonal in pixels, then divide it by the diagonal screen size in inches. That is exactly what this calculator does.
Dot pitch is the physical distance between the centres of two neighbouring pixels. It is simply 25.4 divided by the PPI, so a higher PPI always means a smaller dot pitch.
Only up to the point your eye can resolve. Viewing distance matters more than the raw number, which is why a 60-inch TV at 80 PPI and a phone at 460 PPI can both look perfectly sharp.
Not quite. PPI describes pixels on a display, DPI describes ink dots a printer lays down. The arithmetic is similar but the two numbers are not interchangeable when preparing print artwork.