I’m trying to find out whether there is more than one page of posts (I’ve set my posts per blog page to 5 in the reading settings) in a custom category template.
I would think the global query would have the total number of pages as a property but I can’t find the call to it.
This shows the number of pages for the current query. If you want to determine the actual number of posts found by the current query, you may use
$wp_query->found_postsSource:- http://codex.wordpress.org/Class_Reference/WP_Query
To this day, Mridul Aggarwal answer is not only valid, but vital to use the_posts_pagination() function in some loops scenarios