I have chatted with multiple new authors this week. On multiple occasions, they asked about the number of pages in a book?
Page count is a fuzzy number. It depends on lots of variables like font type and size, margins, line spacing. Therefore, don't bother using a page count. Word count is King!
MS Word keeps a constant word count in the bottom left side info bar. Every word processor keeps a word counter.
--Always use word count when talking about your book size!