The pages of a document, especially when it’s purpose lies in being printed, follow certain standards when it comes to the Page Size (also called paper size). When checking a document such as a PDF, RTF or Microsoft Word document, can give you valuable clues as to which size the document is optimized for.
The display of paper size can differ greatly. What they have in common, however, is that they follow uniform standards. These can vary across countries, yet there are some international standards that are used most often.
Depending on your document, the Page Size is given in one of these two formats or a combination of both:
An example of the first one would be “594 x 840 pts”. The latter could simply read “Letter” or “A4”. Combinations are also possible, such as “595.32 x 841.92 pts (a4)”.
For a more extensive list of Page Size standards and their actual dimensions, check out this article: All You Need To Know About Paper Sizes