I recently got the OS X 10.10.3 update, which got me Photos for OS X and the opportunity to use iCloud Photo Library. However, I'm a little worried about maxing out my iCloud storage if I upload every photo on every device I own, since I currently only have the free 5GB and I'm already cutting it kind of close.
I was wondering, is there a way to figure out how much iCloud storage my combined photo libraries (MBP, iPhone, and iPad) would eat up before turning on iCloud Photo Library and learning the hard way?