Each bag of PrettyLitter is designed to last an entire month for one medium-sized cat in an average-sized litter box (12" x 16"). After you pour your PrettyLitter into your litter box, use the ruler card in the bag to make sure you are getting the proper 2" of depth. If you aren't getting the proper amount of depth in your litter box, talk to us! We'll set you up with the perfect subscription plan for your needs. Our team can be reached at (800) 838-3381 or at meow@prettylitter.com.