Litter Robot 4 vs 5: I Bought the 4 on Purpose
Same self-cleaning box. The 5 adds a sensor that pings your phone about cat poop. For a healthy multi-cat house, that's $100 for nothing.
Winner: the Litter Robot 4 for almost every household. I researched both before I bought, picked the 4 on purpose, and a year in with 3 cats it's the single most life-changing piece of cat gear I own. The 5 is a fine appliance, it's just a $100 upgrade to get notifications I have no use for.
This is the comparison. What's the same, what's different, and the only situations where the 5's price actually pays off. For the rest of the gear that earned a spot in my house (Litter Hopper add-on, smart feeders, the Dyson that catches the litter scatter), the cat home gear guide covers it.
The spec sheet
Side-by-side: what you're paying for
The Litter Robot 4 vs 5 thing is mostly one feature. The mechanism is the same, the cleaning is the same, the app is the same. The 5 adds a sensor and bumps a couple of numbers up.
| Feature | Litter Robot 4 | Litter Robot 5 |
|---|---|---|
| Retail price | $699 | $799 |
| Sale price (a few times a year) | ~$499 | ~$649 |
| Max cats | 4 | 5 |
| Cat weight range | 3 to 25 lb | 3 to 30 lb |
| Waste drawer capacity | ~7 to 8 days (1 cat) | ~10 days (1 cat) |
| WasteID sensor | No | Yes (urine vs solid + weight) |
| App notifications about cat poop | No | Yes |
| Carpet tray | Sold separately | Built-in |
| Cycle noise | ~3 min mechanical hum | ~3 min mechanical hum |
| Warranty | 18 months | 18 months |
Read that table and the difference is one row. WasteID. Everything else is the same product or a 2 day stretch on the drawer. You're paying $100 for the sensor.
The one real difference
How they actually differ
WasteID is a load cell and a moisture sensor inside the globe. When a cat steps in, the unit weighs the cat. When the cat leaves, it weighs the waste, and the moisture sensor decides if it was urine or solid. That data goes up to the Whisker app, broken out per visit, charted over time. In a single-cat house it can roughly tell whose visit it was, in a multi-cat house it can usually tell who is who if the cats are different weights, and it can't tell at all if two of your cats are within a pound of each other.
That's the entire feature. Everything else about the 5 is the 4 with rounder corners. Same globe, same bonnet, same step in height, same 3 minute cycle, same Whisker app for scheduling and remote start, same standard 13 gallon kitchen bag in the drawer, same sealed waste, same litter compatibility. If you stood the two units next to each other with the front panels covered, you could not tell the cleaning apart.
The 5's drawer is taller, so you get about 10 days for one cat instead of 7 to 8. With 3 cats my 4's drawer fills in 2 to 3 days, the 5's would stretch that by a day, maybe two. The weight ceiling moves from 25 lb to 30 lb, which only matters if your cat is genuinely big. The carpet tray is built into the 5's base instead of a $40 accessory on the 4. Roll all that together and it's a real but small set of upgrades.
The pitch on WasteID is health monitoring. In practice it's data without a doctor. Healthy cats produce roughly the same urine and solid count every day, the chart looks like a chart, and there's nothing for you to do with it. The first week is interesting. After that you stop opening the app for it. I've talked to LR5 owners who turned the notifications off because the phone buzzing every time the cat takes a leak gets old fast.
When the 5 earns the premium
When the LR5 actually makes sense
There are three real cases where the 5 is the right call.
Your vet asked for the data. If you have a cat with chronic kidney disease, a recurring UTI, diabetes, or another condition where bathroom frequency and volume matter, WasteID is a logger your vet can actually use. That's the use case the feature was built for and it's the one where the $100 pays off. Show up to a vet appointment with 60 days of urine-vs-solid counts and visit weights and the conversation gets a lot more useful than "I think she goes about normal."
Your cat is over 25 lb. The 4 caps at 25 lb. The 5 goes to 30. For a Maine Coon, a Norwegian Forest Cat, or any heavy mixed breed near the ceiling, the 5 is the safer call. The weight sensor in the 5 is what stops the rotation if the cat re-enters mid-cycle, and it's calibrated for the bigger range.
You're a numbers person and you'll actually use the app. Some people genuinely enjoy seeing the chart. They'll catch a 2 day pattern change that I'd miss. If that's you, fine, the 5 is built for that. Just be honest about whether you'll actually open the app after week one.
Outside those three, the 5 is a $100 upgrade for a feature that doesn't change the box's job. The job is to clean itself. The 4 does that.
More cat home gear reviews coming
I'm working through the rest of the gear in my 3 cat house. The Litter Hopper add-on, the smart feeder I actually trust, the robot vacuum that catches the litter scatter. Drop your email if you want the next one when it's up.
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The price math
What you actually pay
Retail is $699 for the 4 and $799 for the 5. Nobody should pay retail. Whisker runs sales on their own site multiple times a year, Black Friday, Cyber Monday, Memorial Day, a spring promo. The 4 hits about $499 on those sales, the 5 hits about $649. Costco carries the 4 with bundled accessories a few times a year at a real discount. eBay has a steady stream of lightly-used returns, usually $400 to $500 for a unit that's a few weeks old.
The cheapest legitimate path is Whisker's official refurb program. Same 18-month warranty as a new unit, about $150 off retail, ~$549 for a refurb 4 when it has stock. That's where I bought mine, $499 on a Whisker sale. A year in, no issues, the warranty is still active and I haven't needed it.
Run the math both ways. A new 5 at $649 on sale vs a refurb 4 at $549. That's $100 for the sensor and a built-in carpet tray. A new 4 at $499 on sale vs a new 5 at $649 on sale, same $150 difference, same conclusion. The carpet tray is a $40 accessory if you want it on the 4. So the real WasteID premium is closer to $60 to $100 depending on which sale you catch. Still not worth it for a healthy cat.
Where to buy
Where to buy the Litter Robot 4
Whisker's own site is where the deals run. The refurb listings cycle in and out of stock, the new units go on sale roughly quarterly. Costco carries the 4 with bundled mats and a starter litter pack a few times a year. eBay's "lightly used returns" listings are real and usually fine, just no warranty. Amazon carries it, but Amazon rarely beats Whisker's own discount and Whisker honors its warranty more cleanly when the unit came from them.
Frequently asked
FAQ
Is Litter Robot 5 worth the extra $100?
Not for most homes. The $100 between the 4 ($699) and the 5 ($799) buys you WasteID, a sensor that distinguishes urine from solid waste, weighs each visit, and uploads it to the Whisker app. Useful if your vet asked for that data. For a healthy multi-cat house it's $100 for notifications nobody asked for.
What's the difference between Litter Robot 4 and 5?
The mechanism is the same. The 5 adds WasteID, a sensor that tells urine from solids and weighs each cat by visit. The 5 also has a slightly bigger waste drawer (~10 days vs ~7 to 8 days for one cat), a higher cat-weight ceiling (3 to 30 lb vs 3 to 25 lb), and a built-in carpet tray that's a paid accessory on the 4. That's it. The cleaning, the app control, the noise, the cycle time, all the same.
Should I buy Litter Robot 4 or 5 for multiple cats?
The 4 is fine for up to 4 cats. The 5 is rated for 5. With my 3 cats the 4's drawer fills in 2 to 3 days instead of the 7 to 8 days quoted for one cat. The 5's bigger drawer would stretch that by maybe a day. WasteID is less useful in a multi-cat house anyway because the sensor can't always tell which cat made the visit unless your cats are very different weights.
Does Litter Robot 5 actually monitor cat health?
It logs urine vs solid frequency and the weight of the cat at each visit. That's data, not diagnosis. A vet can use it to track a cat with kidney disease or a UTI. Without a vet on the other end of the data, you're getting alerts about your cat's bathroom habits and there's nothing to do with them. Healthy cats don't need this.
Is Litter Robot 4 still being sold?
Yes. Whisker still sells the 4 new on their site at $699 and discounts it to about $499 on Black Friday, Cyber Monday, and a couple of spring promos. Costco runs bundle deals a few times a year. The official refurb program is the cheapest path when it has stock, same warranty, about $150 off retail.
Is Litter Robot 5 quieter than 4?
Not in any way you'd notice. Both run a steady mechanical hum for about 3 minutes per cycle. Neither is silent, neither is disruptive. Whisker has not advertised a noise reduction on the 5 and I haven't seen one in side-by-side videos. If quiet is the deciding factor, the 4 and the 5 are the same answer.
Can I save money buying Litter Robot 4 refurbished?
Yes. The Whisker refurb program runs about $150 off retail and carries the same 18-month warranty as a new unit. Stock comes and goes. eBay has a steady stream of lightly-used returns at similar prices but with no warranty. I bought mine refurb on a Whisker sale for $499 and it's a year in with no issues.
Does Litter Robot 5 work better with large cats?
If your cat is over 25 lb, yes. The 4 is rated 3 to 25 lb. The 5 goes up to 30 lb. For a Maine Coon or a heavy mixed breed near the ceiling, the 5 is the safer call. For any cat under 25 lb, the 4 fits the same and the weight ceiling is irrelevant.
Will Whisker discontinue the Litter Robot 4?
Not announced. Whisker still sells, ships, and supports the 4 and ran the Litter Hopper add-on for it in 2025. The 5 launched alongside the 4 rather than replacing it. Even when a discontinuation comes, Whisker has supported the previous generation for years past sunset, parts and bonnets for the Litter Robot 3 are still in stock. Buying a 4 today is not a short-life purchase.
Litter still tracks out of either box, that's a vacuum problem not a litter robot problem. The Dyson 360 Vis Nav is what catches the scatter at my house, runs twice a day, and the bin shows the litter every time.
How I tested
The bar this comparison had to clear
Bought the 4 at retail
Paid $499 on a Whisker sale, $200 off the $699 retail. No review unit, no Whisker freebie. Refurb so the warranty was active if I needed it.
Researched the 5 before buying
Read the WasteID spec sheet, watched the side-by-side videos, talked to LR5 owners. Picked the 4 on purpose to skip a feature I didn't want, not because I missed the 5 existed.
A year of use, 3 cats
A year in my house with my 3 cats, including 2 outdoor rescues. Cycles run 6 to 8 times a day, drawer fills every 2 to 3 days, deep clean every 4 to 8 weeks. The decision still feels right.
This comparison is part of the cat home gear guide. The full Litter Robot 4 review covers the year-with-3-cats experience in detail.