How Sharp Is That Screen?

Two monitors can share a resolution yet look very different — a 27" 4K panel is far denser than a 43" 4K TV. This monitor DPI calculator computes pixels per inch from resolution and diagonal size, the number that actually determines sharpness.

The Math

The Pythagorean theorem gives the diagonal in pixels: √(w² + h²). Dividing by the diagonal in inches yields PPI. Dot pitch, the pixel spacing in millimeters, is its reciprocal (25.4/PPI). The same two inputs also reveal aspect ratio and physical dimensions.

What to Look For

For office work and reading, aim above ~100 PPI; for photo editing and design, 140+ keeps fine detail crisp. Phones and laptops push past 200. Run your own screen through the calculator — you may be surprised how dense (or sparse) your pixels really are.