Your Cat Can't Tell You Something's Wrong. Their Litter Box Can.

Petivity is a rectangular smart scale — just 2.72 inches tall — that sits underneath your cat's existing litter box. It uses multiple pressure pads and an AI model (trained on over 300,000 video-recorded cat events, according to Purina) to determine which cat visited, whether they urinated or defecated, how long they stayed, and how much they weigh.

The device connects to a free companion app (iOS and Android) via Bluetooth and your home Wi-Fi. After a roughly 5-7 day training period where you help label events, the AI learns to identify each cat by weight and starts compiling daily logs, weight trend graphs, and health alerts automatically. If your cat's weight shifts or bathroom frequency changes significantly, you get a push notification on your phone.

Purina developed the system over a decade with input from veterinarians, behaviorists, and data scientists. It's designed to flag changes that may be associated with conditions like UTIs, kidney disease, diabetes, hyperthyroidism, and obesity — though it is explicitly not a diagnostic tool and should not replace veterinary care.

If you have two or more cats, monitoring who's doing what in the litter box is nearly impossible without separating them — which is stressful for both you and the cats. Petivity solves this by using weight to distinguish between cats. During the initial training period, the app asks you to confirm which cat used the box after each event. Once the AI has enough data (usually around 8 labeled events per cat), it takes over automatically.

In practice, this works well when your cats have noticeably different weights. If two cats are within a pound or so of each other, the AI can struggle and occasionally swap them. Purina says it supports up to 5 cats per household, and you can set up multiple monitors if you have multiple litter boxes (one monitor per box is required).

For multi-cat households with cats of similar weight, expect to occasionally correct mislabeled events in the app. The good news: the app lets you edit any event, and each correction helps train the AI further.

Across multiple independent reviews, the consensus is that Petivity is mostly accurate but not flawless. WIRED gave it an 8/10, noting it occasionally failed to record visits and sometimes marked actual eliminations as 'entered but did not use.' Wirecutter found weight readings were consistently within 1-2 ounces of a dedicated pet scale, but noted that about 20% of productive trips were mislabeled as 'no elimination.' Cats.com rated accuracy 3.5/5, citing occasional cat swaps and weight fluctuations.

The main accuracy issues stem from three sources: cats with similar weights confusing the AI, combo events (peeing and pooping in one visit) that the system struggles to parse, and physical setup issues like an unbalanced scale or the litter box touching a wall. Purina actively addresses these in app updates and provides detailed setup guidance to minimize errors.

The takeaway: treat Petivity data as a powerful early-warning system, not a diagnostic instrument. When it flags something unusual, verify with a physical check of the litter box and consult your vet. The real value is in trend detection — catching a gradual weight loss or a sudden spike in visit frequency — rather than expecting 100% accuracy on every single event.

The three most popular cat health monitoring approaches each take a different angle. Petivity is a scale that works with your existing box. Litter-Robot 4 is a self-cleaning litter box with built-in weight tracking. PrettyLitter is a color-changing health-monitoring litter.

Petivity wins on price, cat acceptance (no new box to get used to), and depth of individual-cat data — it's the only option that distinguishes between urination and defecation and identifies individual cats by weight. Litter-Robot 4 wins on convenience (it actually scoops for you) but costs $699 and doesn't currently identify individual cats or track elimination type. PrettyLitter is the cheapest entry point but only provides chemical indicators (pH, blood presence) and doesn't track weight or frequency.

For cat parents whose primary goal is health monitoring rather than automated cleaning, Petivity offers the best data-to-dollar ratio by a wide margin.

Physical setup is straightforward: slide the monitor under your litter box, ensuring at least 1 inch of clearance on all sides. Power it with the included cord or 6 AA batteries (also included). Download the Petivity app, sync via Bluetooth, connect to your 2.4 GHz Wi-Fi, and create a profile for each cat (gender, age, body condition, diet).

The first 5-7 days are 'training mode.' Every time a cat uses the box, you'll get a push notification asking you to confirm which cat it was and what they did (urinated, defecated, or no elimination). This requires you to be relatively available during that first week — if you work outside the home, expect the training period to stretch a few days longer.

Once training is complete, the app runs hands-off. You'll still receive health alerts when something changes, and the app may periodically ask you to verify a few events to recalibrate. You can also opt to receive a notification every time a specific cat uses the box — handy if you're actively monitoring a sick or senior cat.