Display density PPI comparision.

What Is Pixel Density And Pixels Per Inch (PPI)?

Pixel density indicates how many pixels per inch (PPI) there are on a display. The higher the pixel density, the more detailed the picture is. In contrast, displays with low pixel density will have a more pixelated image quality with duller details.

Recommendation for pen display: 160 ppi minimum

Avoid: lower than 120 ppi.

Galaxy S Ultra = 498~505 ppi

Galaxy Tab = 274 ppi

Galaxy Tab Plus = 266 ppi

Galaxy Tab Ultra = 239 ppi

iPhone = 460 ppi

iPad mini = 327 ppi

iPad Pro = 264 ppi

4k 13.3" = 331 ppi

4k 15.6" = 282 ppi

4k 18.4" = 239 ppi

4k 21.5" = 205 ppi

4k 23.8" = 185 ppi

4k 27" = 163 ppi

1440p 13.3" = 220.8 ppi

1440p 15.6" = 188 ppi

1440p 21.5" = 136.6 ppi

1440p 23.8" = 123.4 ppi

1440p 27" = 108.8 ppi

1080p 13.3" = 165.6 ppi

1080p 15.6" = 144.2 ppi

1080p 21.5" = 102.4 ppi

1080p 23.8" = 92.6 ppi

1080p 27" = 81.6 ppi

For more explanation, check out this article: https://www.displayninja.com/what-is-pixel-density/

DPI/PPI calculator: https://www.sven.de/dpi/

7pen doc: https://docs.thesevenpens.com/drawtab/guides/pen-displays/choosing-the-right-display-resolution-for-a-pen-display