I researched dozens of automatic litter boxes across retailers and read their customer reviews for insights into overall performance. Self-cleaning litter boxes run small, so I considered only models made for multiple-cat households because they’re bigger, which gives your cat a bit more space. For testing, I looked at several attributes. Scooping and processing time: I soiled each litter box with our stand-ins for cat pee and poop (¼ cup of water and halfway-melted chocolate, respectively) and assessed how well and how quickly the litter box scooped out the mess. Noise level: I sat a foot away from each litter box and used the smartphone app dB Volume to record how loud each model was when it activated. Those that measured at or below 50 decibels, the same level as a household conversation, are less likely to scare a cat or annoy a human.