Litter-Robot 4 Vs. 3 Connect 2025 - Forbes Vetted

The name “Litter-Robot” has practically become synonymous with self-cleaning litter boxes. While there are other reputable brands in the space, Litter-Robot’s models are known as the crème de la crème of the category. Since the first Litter-Robot launched in 2000, the brand has released numerous models improving on the original automatic litter box’s design. Today, the newest and best-selling models are the Litter-Robot 4 and the Litter-Robot 3 Connect. Both are Wi-Fi–enabled and have advanced features that can detect when your cat is using the bathroom, for example, and when the waste drawer needs to be emptied.

The Litter-Robot 3 Connect and Litter-Robot 4 are the brand's two newest models. Here's how the ... More self-cleaning litter boxes compare.

I have both models in my home, and my three cats use each one regularly. While the two self-cleaning litter boxes operate similarly, they have some notable differences in terms of their advanced safety features, sifting systems and odor control. To help you decide which would be a better fit for you and your cats, I break down the biggest differences between the two models in this Litter-Robot 4 vs. 3 Connect comparison guide. Before I jump into the specifics, though, here’s a general overview of each of the automatic litter boxes.

Whisker

Footprint: 22 x 27 x 29.5 inches | Weight: 24 pounds | Minimum cat weight: 3 pounds | Entryway: 15.8 x 15.8 inches | Available colors: Black or white, with various bezel options

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The Litter-Robot 4 is the brand’s newest model. Designed with multi-cat households in mind, the Wi-Fi–enabled litter box can accommodate up to four cats, thanks to a larger waste drawer and real-time monitoring of waste and cat litter levels. What’s more, it has sensors that make it safe for felines as small as 3 pounds. Some other standout features of the Litter-Robot 4 include a wider entryway and advanced odor control.

Whisker, Litter-Robot’s parent company, calls the model the “smartest, quietest self-cleaning litter box for cats,” and I have to agree. After testing several automatic litter boxes, including the Litter-Robot 3 Connect, I named the Litter-Robot 4 the best self-cleaning litter box overall. It comes in two basic colors, but you can choose from different bezel options to give it an upgraded look.

Litter-Robot

Footprint: 24.3 x 27 x 29.5 inches | Weight: 24 pounds | Minimum cat weight: 5 pounds | Entryway: 10.3 x 15.3 inches | Available colors: Grey or Beige

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Cons:

There are two available versions of Litter-Robot 3, and the Connect is the Wi-Fi–enabled model. Like the Litter-Robot 4, the litter box connects to the companion app (called the Whisker app), though it has more limited functionality. It’s also louder, has a smaller waster drawer and doesn’t control odor as well as the Litter-Robot 4. But the 3 Connect still has a lot to offer. Its best features include an effective safety system, reliable operation and waste drawer alerts. Additionally, the Litter-Robot 3 Connect is more budget friendly, making it a good option for those who want the convenience of a self-cleaning litter box for less. Just note that cats must be at least 5 pounds to use this model, which comes in two colors: Grey and Beige.

Now that you have a general overview of each of the models, here’s how they compare in terms of setup, design, odor control, sensors, noise, deep cleaning and price.

Simply put, setup for both models is a cinch. They come fully assembled, so you just have to take them out of the box and plug them in. The biggest difference is how you connect (and reconnect) them to the Whisker app. To sync the robots with the app, you scan a QR code that’s on the machine. The Litter-Robot 3 Connect has the code in the back of the machine at the base. The Litter-Robot 4’s code, on the other hand, is more conveniently positioned under the waste drawer.

While this isn’t a big deal for the initial setup, the positioning of the QR code makes a difference if the Litter-Robot disconnects from the app and needs to be reconnected. When I need to reconnect the Litter-Robot 3 Connect, I have to take it out of the credenza it’s in and spin it around to find the QR code. With the Litter-Robot 4, I can just pull the waste drawer out and it’s right there—no need to fuss with the positioning.

The design is the biggest difference between the Litter-Robot 3 Connect and 4—and it’s not just about the looks. The construction also factors into odor control and how many cats the Litter-Robot can accommodate.

Let’s start with size. The Litter-Robot 4 is narrower than the Litter-Robot 3 Connect. While they have the same height (29.5 inches) and depth (27 inches), the Litter-Robot 4 measures 22 inches wide, compared with the 24.5-inch width of the Litter-Robot 3 Connect. At the end of the day, though, both of these Litter-Robots are big. Neither one of them is going to blend in seamlessly with its surroundings, so you have to be willing to sacrifice some space regardless of which model you pick.

The Litter-Robot 4 self-cleaning litter box, pictured in my home.

That said, the Litter-Robot 4 has some design upgrades that can benefit your cat. For starters, the entryway is much wider: 15.75 inches compared with the Litter-Robot 3 Connect’s 10.25 inches. While my cats never seem bothered by the smaller opening of the latter, they definitely stick out of it more when they’re doing their business; they just seem more comfortable in the Litter-Robot 4. The step into the entryway is also closer to the ground on the newer model, so it can be a better option for smaller cats or senior cats with mobility issues. (Whisker does sell ramps to make the taller step on the Litter-Robot 3 Connect more manageable, but with the Litter-Robot 4, you don’t need it.)

Another notable difference is the waste drawer. The Litter-Robot 4’s drawer has an overall smaller footprint, though the area that collects waste is larger. This means you don’t have to change the trash bag as often. The Litter-Robot 4’s drawer also has a more rectangular shape, so waste spreads out more evenly. With the Litter-Robot 3 Connect, I often notice that clumps pile up in the center of the drawer, sending false signals to the sensors that the waste drawer is full. That doesn’t happen with the Litter-Robot 4. Additionally, the trash bag fully covers the waste drawer in the Litter-Robot 4. The Litter-Robot 3 Connect has clips inside the waste drawer to keep the trash bag in place, but if it’s not secured properly, it can cave in, creating a pretty annoying mess.

This ties into design, but it’s worth calling out odor control separately since it’s one of the most vital parts of a litter box. While both models have carbon filters that need regular replacing, the Litter-Robot 4 is much more effective at trapping odors than the Litter-Robot 3 Connect, even with a full waste bag. Whisker says this is because the waste drawer is deeper and has a tighter seal.

I rarely smell any waste in the Litter-Robot 4—unless it’s fresh and still in the chamber before cycling. With the Litter-Robot 3 Connect, I can tell when it’s full just by the way it smells. It’s not as strong as an open litter box, to be sure, but things do get musky if you don’t keep up with cleaning.

The safety sensors also got an upgrade in the Litter-Robot 4. The Litter-Robot 3 Connect has weight sensors inside the globe that are triggered when your cat starts to enter or is inside the machine. These sensors stop or delay a cleaning cycle to keep your cat safe. While these have been reliable for me—the Litter-Robot 3 Connect has never, for example, cycled with my cat in the way—the sensors aren’t technically as effective as the ones in the Litter-Robot 4.

The newest version of the self-cleaning litter box has both laser and weight sensors so it can trigger the stop mechanism more readily, even if your cat is just peeking into the opening and hasn’t put their full weight into the globe. While this ensures a faster response time, it also means that cats who weigh just 3 pounds can safely use the Litter-Robot 4. For comparison, the minimum weight for the Litter-Robot 3 Connect is 5 pounds.

These sensors are also so advanced that they can tell you which cat in a multi-cat household is using the litter box. While the scale isn’t totally accurate—for example, it registers my 10-pound cat as weighing 7 pounds—it’s still a useful tool for tracking the bathroom habits of each of your pets. If one of your cats isn’t using the bathroom as often as they should (which can be a sign to call the vet), this feature can help alert you, says Jacob Zuppke, CEO and president of Whisker.

My cats' recent bathroom activity, as recorded by the Litter-Robot Whisker app.

While the laser sensors make for a safer machine, they also make it more sensitive—I’ve had more accidental triggers with the Litter-Robot 4 than the Litter-Robot 3 Connect. Though those incidents can be annoying, Zuppke says the brand’s engineering team is always working behind the scenes to find the right level of sensitivity for these sensors. When I first got the Litter-Robot 4, the sensors were much touchier than they are now; thanks to firmware updates, they’re a bit less reactive. And the sensors aren’t the only part of the litter boxes the engineering team is constantly working on to improve. Any time you update one of the Wi-Fi–enabled models via the app, your litter box downloads any changes made. (It’s the same concept as iPhone updates.)

In addition to safety, the upgraded sensors have one other strength. When connected to the app, the Litter-Robot 3 Connect can only tell you if the waste drawer is full and needs to be emptied. Meanwhile, the sensors in the Litter-Robot 4 can monitor both waste and litter levels, so you can see exactly how full the waste drawer is and whether you need to add litter to the globe.

Noise, or lack thereof, is another major difference between these two models. The Litter-Robot 4 is significantly quieter than the 3 Connect—I can barely hear it when it’s running. The Litter-Robot 3 Connect isn’t obnoxiously loud, but I’d say it’s at least twice as loud as the Litter-Robot 4. (The sound level is similar to an electric can opener or a bathroom fan.) For what it’s worth, the sound doesn’t bother my cats at all. If you have more skittish felines, though, you may want to upgrade to the Litter-Robot 4 just for this.

Deep cleaning takes about the same amount of effort for each model, and Whisker recommends you do the chore at least every three months, depending on how many cats you have. To really get the litter box clean, you have to take everything apart, thoroughly wash it and then let all the parts dry completely before reassembling it. It also requires vacuuming where the waste drawer sits, and there are lots of nooks and crannies in each of the machines that make this a pain. It takes at least an hour to do every time, and neither machine has an edge here.

Perhaps the most obvious difference between the Litter-Robot 3 Connect and the 4 is the price. The Litter-Robot 3 Connect retails for $549, while the Litter-Robot 4 is $699—that’s $150 more. In my opinion, the upgrades are worth the higher cost, especially when you consider how long these litter boxes are meant to last. I’ve owned the Litter-Robot 4 for a year and a half so far, so it breaks down to an extra $8 or so each month. And if you can’t swing the upfront cost, Whisker offers payment plans through Affirm.

If it’s within your budget, I recommend purchasing the Litter-Robot 4. While I’m happy with the performance of both machines, the newer model’s design is such a massive upgrade. It’s considerably better with odor control, able to hold more waste and much quieter, which I believe are worth the extra cost.

Now, if you already own the Litter-Robot 3 Connect and it’s working well for you, I don’t think you need to toss it in favor of the Litter-Robot 4. If you want to add a second litter box, though, I’d go with the 4. And if you need more convincing, check out features director and cat mom Kim Peiffer’s full review of the Litter-Robot 4.

I’m Lindsay Boyers, the executive strategy editor at Forbes Vetted and a self-proclaimed cat lady who has three Siberian cat mixes terrorizing (er, enriching) my home.

In short, yes, it’s worth upgrading to the Litter-Robot 4, even though it costs $150 more than the Litter-Robot 3. With the Litter-Robot 4, you get better odor control, a bigger waste drawer and an overall smaller footprint (with a more aesthetically pleasing design). The Litter Robot 4 also has an upgraded weight sensor that makes it a better pick for multi-cat households since you can monitor each cat’s bathroom usage.

Both Litter-Robot models are backed by one-year warranties, but in my experience, the lifespan is much longer. I’ve owned the Litter-Robot 3 Connect for four years and the Litter-Robot 4 for one and a half years, and both models are still going strong. According to Zuppke, keeping up with regular software and firmware updates through the app can help maximize the life of your Litter-Robot.

I’ve found the Litter-Robot 4 to be significantly quieter than the Litter-Robot 3 Connect. When running, the latter is about as loud as an electric can opener or a bathroom fan, which may be bothersome for more skittish cats. The former, on the other hand, makes very little noise when it’s cycling—I can barely hear it.

We updated pricing and spec information and added details about our expertise on this topic.