DELL XPS 15

Pixel pitch (computed from PPI; a rectangular estimate, not a measured panel pitch)

86.5 um

Physical size (computed from the rectangle, not the usable area)

13.07 by 7.35 in (33.2 by 18.7 cm)

Aspect ratio (computed)

16:9

Megapixels (computed)

8.29

Looks sharp from (assuming 20/20 vision, one pixel per arcminute)

11.7 in and further

Pixels per degree at an assumed 20 in viewing distance

102.5

Density as a percentage of Windows' 96 PPI reference (a ratio, not a scaling recommendation)

306%

macOS 2x workspace (hypothetical: half the native resolution in points)

1920 by 1080 points

Every row above is computed here from the stated resolution and the stated diagonal. With w and h in pixels and the diagonal in inches: PPI = sqrt(w^2 + h^2) / diagonal, which here is sqrt(3840^2 + 2160^2) / 15; pixel pitch = 25.4 mm / PPI; physical size = pixels / PPI, which is the full panel rectangle and not the usable area, so a screen with rounded corners or a notch has less usable area than the size shown; sharpness distance = 1 / (PPI x tan(1/60 degree)), the distance at which one pixel spans one arcminute for 20/20 vision; pixels per degree = 2 x distance x tan(0.5 degree) x PPI at the assumed viewing distance. Values are rounded to two decimals, and to one decimal for the pitch, the sizes in centimeters, the distances, and the pixels per degree.