Let's simplified the situation, say that the page only contains text. Change the question to how many lines will the page occupy when it is displayed. Even with this largely simplified question, you still cannot have a definitive answer, as the paragraphes can be wrapped around differently because of: 1) the font; 2) the resolution of the screen etc.
On the other hand, even if there is an answer to this question, a page with excessive advertisements on it, is still very unpleasant. You probably should really reduce the number of ads you have on each page, and not waste time to calculate the height.