probably the easiest way to find out for your handwriting is to get a piece of your normal handwritten work on the paper you'd be using and count how many words there are on like the first five (non indented) lines so say you have an average of 12 words per line. Times that by the number of lines, probaby about 20-25 and you have how many words you write on a page.
Then highlight one page of text on any MSword piece of work (I'm guessing you have some saved) and see how many words it is, and compare. (word count in bottom left of screen on 2007, will be "highlighted/total")
Or you can change the font on screen to a size where you have those 12 words per line, then change the line spacing to get the same number of lines on a page as there are on a piece of paper.
Generally for me its one page of normal spaced size 11/12 to two pages written.