Screen PPI calculator
PPI is how many pixels fit in one inch of a screen. Enter a resolution and a diagonal to calculate it, or calibrate with a bank card to measure the screen in front of you.
Calculate PPI
Enter the pixels and the diagonal of any screen. The width and height start as your own screen's estimated resolution.
Enter the width, the height and the diagonal to see the PPI.
The PPI of your own screen
Browsers cannot read the physical size of a screen, so we measure it with a bank card. Match the on-screen card to a real one and save, and we work out your screen's PPI.
Hold a bank card flat against your screen and keep your browser zoom at 100%.
Move the slider to match your card, then save.
What this number means
- PPI is the square root of (width² + height²), divided by the diagonal in inches. Use the real pixel counts of the screen.
- Dot pitch is the distance from one pixel to the next: 25.4 mm divided by the PPI.
- Physical size is the pixels along each side divided by the PPI, which is the width and height of the visible picture.
- Your own screen. The size of a pixel comes from your calibration, typically within a few percent. The PPI also uses your pixel ratio, and display scaling can make that read high (up to about 15% in a scaled mode), so check your device's specifications for exact values.
Common screens
| Screen | Resolution | PPI |
|---|---|---|
| 24-inch Full HD monitor | 1920 × 1080 | 92 |
| 27-inch QHD monitor | 2560 × 1440 | 109 |
| 27-inch 4K monitor | 3840 × 2160 | 163 |
| 32-inch 4K monitor | 3840 × 2160 | 138 |
| 13.3-inch laptop | 2560 × 1600 | 227 |
Calculated from the nominal diagonal with the formula above and rounded. A real panel is a little different.