How much space left on Mathematica notebook?

Dear Friend
I would like know how can tell how much space left on my Mathematica notebook in an A4 paper format. So I would have to use page breaker or pdf generator to address my presentations.

Thank you.

hand working.pdf (81.8 KB)

As far as I know, you can only do this in the vertical direction, though Mathematica does an OK job of the horizontal for you.

Check out: https://reference.wolfram.com/language/ref/menuitem/ShowPageBreaks.html