Basically a
Word document doesn't have pages at all. When you see it displayed in Word it may appear to have pages, but that's because it's using the default page layout information to paginate the document. If you click on the Page Layout tab you'll see all the things you can change -- margins, page orientation, page size, columns, and more -- and which will affect the pagination. And as already pointed out, there are many other things which affect the pagination.
But if, as you say, you're just reading the raw bytes from the .doc file, you don't have any hope of finding out any of those things. You're just reading the document text and the document formatting and other control information as uninterpreted bytes. You can't find out anything at all about the document that way except how many bytes it took Word to store it on disk.