On my computer, First[WindowSize/.Options[EvaluationNotebook[]]] gives me 1432.5 if the notebook has maximum width for my screen.

My screen resolution is 1920*1080 however. So the result can't be in pixels.

What's the unit returned by WindowSize?

Another strange observation: I can make the window narrower, e.g.

SetOptions[EvaluationNotebook[], WindowSize -> {716, 760.5}]. If I look at WindowsSize programmatically I get

WindowSize /. Options[EvaluationNotebook[]]


What causes the extra 0.25 whatever-units width?


1 Answer 1


They are in Points, as documented here.

  • $\begingroup$ Is one point=1/72 inch = 127/360 mm? Does it depend on dpi settings in the operating system (in my case: Xubuntu 20.04). Fortunately the returned value does not depend on the Magnification set for Mma! (I have not tried to alter the operating system's dpi settings: they are shown to be 96 dpi, but if I divide the screen pixel dimensions by the sizes in inches I get ca 142 dpi if I compute it with the results from xrandr | grep -w connected). $\endgroup$ May 16 at 19:11
  • $\begingroup$ It depends on the logical resolution of the display. i.e., what the OS reports, not the physical device. If you set the display to be 200% in your OS's display settings app, it should report 192. You can find this (along with other display characteristics) using SystemInformation["Devices", "ScreenInformation"]. $\endgroup$
    – ihojnicki
    May 16 at 19:20

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