Font sizes points or pixels

I am making lots of parts at the minute and trying to get them consistent with the graphics standards. One thing which seems to have gotten lost in translation - for schematics, the guide says 2.5 points 3.5 points etc. However, the actual standard parts seem to be sized 2.5, 3.5 pixels etc. In inkscape these are different by a significant amount. Which is correct please?

Fonts are nearly always in points… In the schematics it is 2.5 and 3.5 points.

A “point”, in fontspeak, is 1/72 of an inch (about .35mm). To convert to pixels, you have to compute the height (12-point font is 12/72 or 1/6 inch) and on a 300dpi printer, that means 50 pixels. A half-pixel is a mathematical fiction, since a pixel is, by definition, an atomic unit. If you refer to somerhing as 2.5 pixels, it can only be 2 or 3 pixels, nothing else. But if you double the height of a nominal “2.5 pixel” object, it will be 5 pxels high, not 4 or 6. But in the “original” size of 2.5 pixels can only display as 2 pixels (using truncation) or 3 pixels (using rounding). I cannot speak as to Inkscape–I’ve never used it–but you can’t have a meaningful dimension in pixels unless you have a corresponding pixel size. While pixels are assumed to be “square” but it is possible to have non-square pixels (the VGA display had non-square pixels).