Calculate pixels per inch (PPI) and pixel pitch to compare display sharpness across TVs, monitors, and laptops.
Enter your display resolution (for example 3840 x 2160).
Enter the screen diagonal size in inches.
Click Calculate to view PPI and pixel pitch.
PPI is for displays. DPI is usually used for printers, but many people use DPI when they mean screen PPI.
Disclaimer: Sharpness perception also depends on viewing distance, panel quality, scaling settings, and eyesight.
At the same screen size, 4K has much higher PPI than 1080p, which helps with fine text and close seating.