Facebook API how to get the total amount of posts within a time frame

I'm using the Facebook graph API to get monthly snapshots of posts per user.

At the moment I'm using {id}/posts with a since and until flag to get the months worth of data. I've just realised that this data is paginated though so am only getting a maximum of 25 posts within that month time frame.

Is there a fast way, like summary=true, to get a total count for posts, or will I have to loop through the pagination with some logic to see if the posts are still in the specified time frame?

Probably unneeded info, but I'm using Javascript, specifically node.js with the JSForce npm module.