Litter-Robot 4 vs Litter-Robot 5: Should You Pay $100 More?

Whisker sells two camera-free rotating-globe litter boxes side by side: the Litter-Robot 4 at a $699 list price and the newer Litter-Robot 5 at $799. They look almost identical and clean the same way, so the obvious question is whether the extra $100 buys anything your household needs. This comparison walks through what Whisker documents for each, so you can decide. The short version: for most one- to three-cat homes the 4 is the smarter buy, and the 5 earns its premium in a few specific situations.

Quick verdict

Side-by-side specs

*Whisker's own page doesn't give a plain footprint figure for the 5; the dimensions here are from a PetSmart retailer listing. Measure your space with margin.

What the extra $100 actually buys

Three documented differences, and that's about it. Everything else, the sifting mechanism, the 15.75 in entry, the litter rules, the app, the 90-day trial, is the same.

1. One more cat. Whisker rates the 4 for up to 4 cats and the 5 for up to 5. If you have five cats, that's a real reason to step up, though vet guidance still wants more boxes than cats regardless (more below).
2. A higher weight ceiling. The 4 tops out at 25 lb; the 5 goes to 30 lb. For a genuinely huge cat, a Maine Coon pushing past 25 lb, the 5 is the safer fit. Whisker's description of the 5 also mentions added headroom for large breeds.
3. WasteID. The 5 adds WasteID, which separates urine visits from stool visits in the data. The 4 logs visits and weight but doesn't split them that way.

Note what's not on that list: the camera. The camera-equipped model is the separate Litter-Robot 5 Pro (about $899), and in Wirecutter's hands-on test the 5 Pro's app was "extremely glitchy." The plain 5 compared here is weight-based, same as the 4.

Cat size and multi-cat use

This is where the 5 justifies itself or doesn't. Both share the same 15.75 in square entry, so a big cat steps into the same opening. The difference is the weight rating and interior room: the 5's 3–30 lb range and extra headroom suit a cat heavier than 25 lb, while the 4's 3–25 lb covers the large majority of cats. If your biggest cat is comfortably under 25 lb, you're paying for ceiling you won't use.

On cat count, the 4's "up to 4" versus the 5's "up to 5" is a per-unit processing rating, not a substitute for having enough boxes. Whisker is the only maker that publishes a per-cat emptying schedule for the 4: about every two weeks with one cat, weekly with two, twice a week with three, and every other day with four. Expect the 5 to need similarly frequent emptying as cats are added. See our multi-cat self-cleaning guide for the per-cat drawer math.

Weight-based ID has the same limit on both. Whisker's own support page says SmartScale "is not able to accurately distinguish between cats that weigh within one pound of each other." Neither the 4 nor the plain 5 fixes that; it's the camera-and-tag setup on the 5 Pro that's aimed at it. So if telling similar-weight cats apart is your goal, neither of these two is the answer.

Edge: Litter-Robot 5 for five-cat homes and cats over 25 lb; Litter-Robot 4 for everyone else.

The maturity trade-off

The 4 has a track record. It's Wirecutter's top pick after hands-on testing, praised for being spacious, repairable and easy to clean, and Whisker sells replacement parts for DIY repairs, which matters on a machine that runs dozens of cycles. The 5 is newer, and Wirecutter hadn't tested the camera-free version when we checked. Buying the 5 means buying a less independently vetted machine for $100 more. For a lot of households that's the deciding point: the cheaper box is also the more proven one.

Odor, litter and upkeep

Identical on both. Each uses a sealed waste drawer with a carbon filter, and Whisker recommends replacing the filter and OdorTrap packs every 2–4 weeks. Both want a high-quality, standard-weight, clay-based clumping litter; both warn that white or translucent litters can confuse the sensors, and that most plant-based, non-clumping, newspaper and wood-pellet litters don't work. If you want help choosing, see our guide to the best litter for a self-cleaning box and, for smell specifically, how to stop a self-cleaning litter box from smelling.

Health tracking: useful, not a substitute for watching your cat

The 5's WasteID, splitting urine from stool visits, is the one data feature the 4 lacks, and it can be a helpful nudge toward noticing a change early. But both machines share the same blind spot that comes with any automatic box: you no longer see the clumps. Cornell's Feline Health Center lists straining, frequent urination, crying while urinating and blood in the urine as signs of lower urinary tract disease, and warns that repeated unproductive attempts to urinate, especially in male cats, can be an emergency. Treat either app's data as a reason to look more closely, not a diagnosis.

Which should you buy?

Buy the Litter-Robot 4 if:

• You have one to four cats, all under 25 lb.
• You want the most proven machine and the lower price.
• You'd rather put the $100 toward litter, filters or a second plain backup box.

Buy the Litter-Robot 5 if:

• You have five cats, or a cat heavier than 25 lb (up to 30 lb).
• You specifically want WasteID's urine-vs-stool split, or the extra interior headroom for a large breed.
• You're comfortable with a newer model that independent reviewers hadn't fully tested when we checked.

Still deciding between brands rather than between these two? Our best self-cleaning litter boxes roundup compares 20 models, and the Litter-Robot 4 vs ScoopFree SmartSpin head-to-head weighs the 4 against a cheaper rival.

FAQ

Is the Litter-Robot 5 worth $100 more than the Litter-Robot 4?

For most homes, no. The 4 is cheaper and more proven. The 5 earns the premium mainly if you have five cats, a cat over 25 lb, or you specifically want WasteID and the extra headroom.

What's the difference between the Litter-Robot 5 and the 5 Pro?

The plain 5 uses weight-based ID like the 4. The 5 Pro adds a camera (and works with a $29 RFID PetTag) to help tell similar-weight cats apart, at a higher price. Wirecutter found the 5 Pro's app glitchy in testing.

Do the 4 and 5 use the same litter?

Yes. Both recommend a high-quality, standard-weight, clumping clay litter and warn against white or translucent litters that can confuse the sensors, plus most plant-based, non-clumping, newspaper and wood-pellet litters.

Can either tell my two same-weight cats apart?

Not reliably. Whisker's support documentation says SmartScale can't distinguish cats within about a pound of each other, and that applies to both the 4 and the plain 5. For that you'd need the camera-based 5 Pro or another camera model.

Ready to choose? Our picks again

Best for	Pick	Where to buy
Most homes (1–4 cats)	Whisker Litter-Robot 4	Check price on Amazon (paid link)
5 cats or a cat over 25 lb	Whisker Litter-Robot 5	View at Whisker (not an affiliate link)

Not sure yet? Grab our free Self-Cleaning Litter Box Buyer's Checklist (printable PDF) and compare models side by side.

Sources

Prices and specs were checked on Oct 19, 2026. Manufacturers change specs and prices; check the product page before you buy.

1. Whisker: Litter-Robot 4 product page (up to 4 cats, 3–25 lb, 15.75 in entry, price, trial)
2. Whisker: Litter-Robot 4 ongoing maintenance (per-cat emptying schedule)
3. Whisker: Litter-Robot 5 product page (up to 5 cats, 3–30 lb, WasteID)
4. Whisker: Litter-Robot 5 Pro product page (camera version)
5. PetSmart: Litter-Robot 5 listing (Whisker description: headroom for large breeds, 22.2 × 27.25 × 29.9 in)
6. Whisker Support: Litter-Robot 5 inaccurate cat weight (cannot distinguish cats within one pound)
7. Wirecutter: The Best Automatic Cat Litter Boxes (hands-on testing; Litter-Robot 4 top pick; 5 Pro app glitchy)
8. Litter Box Picks: master comparison dataset (every figure with its source URL)
9. Cornell Feline Health Center: Feline Lower Urinary Tract Disease (why watching output matters)