Resolution is how many pixels the display has. Screen size is the physical diagonal in inches. Both together determine sharpness (PPI). Use our screen checker to see all three for your device.
Resolution explained
Resolution is written as width × height in pixels — for example 1920 × 1080 (Full HD). Higher resolution means more detail on screen, but not necessarily a larger physical display.
- HD / 720p: 1280 × 720
- Full HD: 1920 × 1080
- QHD: 2560 × 1440
- 4K UHD: 3840 × 2160
Physical screen size
Screen size is the diagonal measurement of the visible panel, usually in inches. A 6.7" phone and a 6.7" tablet can share the same diagonal but very different resolutions and use cases.
Learn to measure accurately in our measuring guide.
PPI ties them together
Pixels per inch (PPI) combines resolution and physical size. Two 27" monitors can look very different if one is 1080p and the other 4K. Calculate PPI with our PPI calculator.
Apple markets ~326 PPI on many iPhones as "Retina" — meaning pixels are dense enough that most users cannot see individual dots at normal viewing distance.
Which matters when?
- Buying a replacement screen: match physical size and connector; resolution should be compatible.
- Comparing phones: both diagonal and PPI affect how content looks.
- Web design: resolution (viewport) matters more than physical inches.
Check your device now
Use our free screen size checker to detect your exact specs instantly.