Copyfit was written during my art college days, when I did a subject called print theory. And very boring it was too. One of the things we learned was how to work out the number of words on a given page, depending on various things such as leading, type size, measure and page depth.

This program does all the calculating for you. It's a bit pointless, what with these tools called DTP packages to do the stuff for you in a much friendlier way. Yet in the good old days of printing, working this stuff out was vital in order to work out how much paper a book would use according to type size.
  -- Stephen Scott