Enter a screen’s diagonal size and resolution to get its pixels per inch, physical dimensions, megapixels and dot pitch.
What PPI tells you
Pixels per inch is the honest measure of how sharp a screen is — resolution alone means nothing without the physical size it’s stretched across. A 27-inch 4K monitor and a 6-inch 4K phone share a resolution and live in different sharpness worlds. Enter the diagonal and the pixel resolution and this calculator returns the PPI, the screen’s physical width and height, the megapixel count and the dot pitch.
How to use it
- Enter the diagonal size in inches.
- Enter the horizontal and vertical resolution.
- Read the PPI and the derived measurements.
The formula
A worked example
The classic 27-inch QHD monitor — 2560 × 1440 — works out at 108.79 PPI: a 23.5 × 13.2 inch panel, 3.69 megapixels, 0.233 mm dot pitch. That ~109 PPI figure is why 27″ QHD became the desktop sweet spot: sharp at arm’s length without any scaling headaches. The same maths puts a 27″ 4K panel at 163 PPI and a 6.1″ phone at 460.