in reply to Tk Entry and ListBox width

To get the size in pixels of a widget, use:

$EntryWidget->width;

UPDATED: As far as the ListBox is concerned, set geometry of the containing widget (if a Toplevel window), which allows for setting size in pixels, with:

$window->geometry();

or simply play with the options (-extend and -fill) of pack for both the containing widget (probably a Frame) and of the ListBox.

In Section Seekers of Perl Wisdom