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The short answer
Litter-Robot 5 is the right buy for most multi-cat homes — it supports up to 5 cats and a 3–30 lb weight range, and it is the newest platform. Litter-Robot 4 is the right buy if you want the LitterHopper autofill accessory, because it is the only current model that supports it. Litter-Robot EVO is the right buy for one cat in a small space, at 25% smaller than the Litter-Robot 5 and $200 cheaper.
Everything below is drawn from Whisker’s published specifications and comparison chart, not from hands-on use.
Contents
- The three models at a glance
- Price and what changed each generation
- Size and physical specifications
- Cat capacity and weight range
- Waste drawer and emptying interval
- Features that differ
- Accessories and compatibility
- Our Verdict
- How We Researched This
- Sources
The three models at a glance
| Litter-Robot 5 | Litter-Robot 4 | Litter-Robot EVO | |
|---|---|---|---|
| Base price | $799 | $699 | $599 |
| Pro version available | Yes, $899 | No | No |
| Cat capacity | Up to 5 cats | Up to 4 cats | Up to 2 cats |
| Cat weight range | 3–30 lbs | 3–25 lbs | 3–19 lbs |
| Empty every (1 cat) | ~10 days | ~8 days | ~7 days |
| Footprint | 22" x 27" | 22" x 27" | 20.6" x 24.3" |
| Exterior height | 29.9" | 29.5" | 27.6" |
| Globe opening width | 15.75" | 15.75" | 14.85" |
| Interior globe height | 17.5" | 16.5" | 14.5" |
| Step height | 7" | 6.9" | 5.6" |
| Weight, empty | 28.7 lbs | 24 lbs | 21.5 lbs |
| Carpet tray | Built in | $30 add-on | Built in |
| WasteID | Yes | No | No |
| LCD color screen | Yes | No | Yes |
| LitterHopper compatible | Coming soon | Yes, $129 | No |
| Manufacturer-hosted rating | 92/100 (241 reviews) | 89/100 (14,093 reviews) | 94/100 (23 reviews) |
All figures published by Whisker on 2026-09-19. Review counts are manufacturer-hosted aggregates, not independent testing.
Price and what changed each generation
Current base prices are $799 for the Litter-Robot 5, $699 for the 4, and $599 for the EVO. The Litter-Robot 5 Pro adds $100 over the standard 5.
A 3-year extended warranty is a $100 add-on at checkout on all three. Starter bundles are listed at $959 (Litter-Robot 5), $859 (Litter-Robot 4), $729 (EVO), and $1,059 (5 Pro).
The Litter-Robot 3 Connect, discontinued, was listed at $549 before it went away. Whisker’s own discontinuation notice directs buyers to either the EVO ("a similar experience at a similar price point") or the Litter-Robot 5.
What each generation actually changed, per Whisker’s documentation:
- 3 → 4: the OdorTrap System option, SafeCat System with OmniSense detection, QuietSift cleaning cycle, a larger waste drawer, and a wider opening.
- 4 → 5: WasteID waste-type detection, a slightly larger interior globe, improved waste drawer distribution, an LCD display, a 3–30 lb weight range (up from 3–25), and support for up to 5 cats (up from 4).
That last set is the substantive upgrade. The rest is iteration.
Size and physical specifications
The footprint story is simple: the Litter-Robot 5 and 4 have identical footprints at 22" x 27", but the 5 is taller (29.9" vs 29.5") and heavier (28.7 lbs vs 24 lbs empty). The extra height is not wasted — it shows up in interior headroom.
Interior globe height is where the models genuinely separate:
- Litter-Robot 5: 17.5"
- Litter-Robot 4: 16.5"
- Litter-Robot EVO: 14.5"
Whisker’s 4-vs-5 article states the Litter-Robot 5 offers interior globe height "up to 19 inches (depending on litter level)," which is a filled-versus-empty distinction the specification block does not reflect. Whisker also notes both the 4 and 5 share a 15.75" globe opening width.
The EVO is the outlier. At 20.6" x 24.3" it is meaningfully smaller, and its 14.85" opening is narrower than the other two. Whisker’s own positioning is "apartments, snug spots, or just about anywhere," and it says the EVO is 25% smaller than the Litter-Robot 5. That size reduction is exactly why its weight ceiling is lower.
If you are placing any model on carpet, note the difference: the 5 and EVO have a carpet tray built in, while the 4 requires a $30 Carpet Tray accessory to keep SmartScale weight readings accurate. On a firm level floor none of them need it.
Cat capacity and weight range
| Litter-Robot 5 | Litter-Robot 4 | Litter-Robot EVO | |
|---|---|---|---|
| Max cats per unit | 5 | 4 | 2 |
| Minimum cat weight | 3 lbs | 3 lbs | 3 lbs |
| Maximum cat weight | 30 lbs | 25 lbs | 19 lbs |
| Weight-based cat ID | Yes | Yes | Yes |
| Visual (camera) cat ID | 5 Pro only, requires Whisker+ | No | No |
The weight ceiling is the specification that should drive your decision if you have a large cat. A Maine Coon, Siberian, or Norwegian Forest cat can sit close to or above 25 lbs. On a Litter-Robot 4, that cat may not register correctly. On the 5 or 5 Pro, the ceiling is 30 lbs.
The weight floor matters just as much. All three require at least 3 lbs, and Whisker’s support documentation for earlier models explains why: cats below the sensor threshold "may not be heavy enough to trigger the cat sensor," and the manufacturer recommends supervised semi-automatic operation until the cat gains weight. Whisker states kittens of at least 3 lbs are supported on the 5 and 5 Pro. For a kitten under that, none of these boxes self-clean reliably.
Beyond raw weight, Whisker’s comparison chart notes that multi-cat weight-based identification is "automatic for 2+ cat households" on all four current models — but that only works reliably when your cats differ in weight. Two cats within about a pound of each other will be hard to distinguish by weight alone. That is precisely the case Whisker markets PetTag (RFID, sold separately) and the 5 Pro’s camera-based visual identification for.
Waste drawer and emptying interval
This is where the generation gap is easiest to quantify.
| Litter-Robot 5 | Litter-Robot 4 | Litter-Robot EVO | |
|---|---|---|---|
| Published interval, 1 cat | ~10 days | ~8 days | ~7 days |
| Waste level sensing | Monitors any level | Monitors any level | Only notifies when full |
| Litter level sensing | Yes | Yes | Not listed |
Whisker’s 4-vs-5 article attributes the 10-day figure on the 5 to "an extra large waste drawer and better waste distribution," and confirms that Whisker’s own maximum recommendation rose from 4 to 5 cats as a result.
Two practical notes. First, these intervals are single-cat claims. Do not extrapolate linearly — clump volume does not scale perfectly, so a 3-cat household on a Litter-Robot 5 should expect meaningfully less than the naive "10 ÷ 3" figure, and Whisker does not publish multi-cat intervals.
Second, Whisker’s support documentation confirms you can use any bag that fits the drawer, but warns that dark bags can make waste level readings inaccurate, especially when the drawer is empty. The manufacturer’s own liners are $12 for a 10-pack, $25 for 25, or $35 for 50, and the redesigned version is white specifically for reading accuracy. Liner cost is a real line item in long-run ownership; we model it in our five-year Litter-Robot cost breakdown.
Features that differ
WasteID (5 and 5 Pro only). The 5 detects whether a visit was urine or feces. For urine, it delays the cycle so clumps form properly; for solid waste, it cycles immediately for odor control. It also feeds the app’s routine tracking. This is the single feature that does not exist on the 4 in any form.
LCD screen (5, EVO, and 5 Pro). Per Whisker, the color LCD makes error states legible — "no more having to decipher light bar codes." If you have ever looked up a blinking-light pattern, this is a real quality-of-life change. We cover the error-state side of things in our Litter-Robot error code guide.
Dual cameras (5 Pro only). Two 1080p night-vision cameras — one forward-facing, one facing the litter bed. Whisker states the AI is trained to detect and record pets, not people, but also states the camera will record you if you are in the frame with your pet. Visual cat recognition and unlimited live streaming require Whisker+ ($7.99/month or $79.90/year, after a 30-day free trial). Without it, live video is capped at 5 minutes per day.
Safety system. All current models use the SafeCat System with OmniSense detection — "a multi-layer safety system of lasers, weight sensors, and anti-obstruction technology." There is no safety differentiator between the three.
Cleaning access. Whisker’s 4-vs-5 documentation states that over the Litter-Robot 4’s lifetime, sensor cleaning was one of the most common maintenance tasks, and that the 5 improves access to the curtain sensor lens for easier wiping. If you have run a 4 for years, that is a maintenance improvement worth knowing about.
Durability. Whisker states the 5’s globe uses scratch-resistant ABS plastic and a reduced-size globe liner to prevent tearing, making it more durable for cats that claw. Whisker also states the 5 has an appliance-grade finish and metalized release handles.
Whisker+ features. Whisker+ applies to the Litter-Robot 4, 5, 5 Pro, and EVO. It unlocks bathroom habit tracking, daily per-cat summaries, patterns, and up to 2 years of activity history. Notably, Whisker confirms that without Whisker+, SmartScale weight tracking and device features "remain free to use" on all four models. Whisker+ is not required for the box to function on any model.
Accessories and compatibility
Whisker’s accessory compatibility rows reveal real differences.
| Accessory | Litter-Robot 5 | Litter-Robot 4 | Litter-Robot EVO |
|---|---|---|---|
| LitterHopper autofill | Coming soon | Yes ($129) | Not compatible |
| PetTag | Yes | Yes | Yes |
| Ramp | Yes | Yes ($65) | Yes |
| Backup Battery | Yes ($40) | Yes ($40) | Yes ($40) |
| Carpet tray | Built in | $30 add-on | Built in |
| Custom bezel | Coming soon | Yes ($35) | Not listed |
| OdorTrap packs | Yes | Yes | Yes |
| Waste drawer liners | Yes | Yes | Yes |
| Carbon filters | Yes | Yes | Yes |
The LitterHopper is the decisive accessory. It dispenses up to 13 cups of litter automatically, holds enough that Whisker says adding 17 lbs of standard clay litter fills both the globe and the hopper, and only works with the Litter-Robot 4. It is not compatible with the EVO, the 5, or the 5 Pro. The Litter-Robot 5 row currently reads "coming soon."
If automated litter refilling is something you specifically want today, that single fact overrides the Litter-Robot 5’s other advantages.
Consumables are shared across models. Waste Drawer Liners are compatible with any Litter-Robot model. Carbon Filters ($7.80 for a 2-pack on subscription, $19.50 for a 6-pack) fit the 4, 5, 5 Pro, and EVO but not the 3. OdorTrap Packs are $15 for a 3-pack, $30 for 6, $50 for 12, and need replacing every two weeks. The Backup Battery is $40 and gives 24–48 hours of reserve power, rated on 10 cleaning cycles per day.
Shared consumables are a real advantage: it means moving between models does not strand you with a stockpile. Our cross-brand consumables comparison shows how unusual that is.
Our Verdict
Litter-Robot 5 ($799) is our pick for most buyers. It is the only current model rated for 5 cats and 30 lbs, it has the longest published drawer interval at 10 days, and WasteID plus the LCD screen are genuine functional additions rather than cosmetic ones. If you have 3+ cats or a large cat, the 4 cannot serve you and the EVO definitely cannot.
Buy the Litter-Robot 4 ($699) instead if you have 1–2 average-sized cats and you want the LitterHopper. At $699 plus $129 you are at $828 for automatic litter refilling that no other Litter-Robot model currently offers. You also get a 14,093-review track record that the newer models simply have not accumulated yet.
Buy the Litter-Robot EVO ($599) instead if you have one cat under 19 lbs and limited floor space. At 20.6" x 24.3" it is the only one of the three that fits a genuinely tight spot, and the $200 you save over the 5 is real money.
Buy the Litter-Robot 5 Pro ($899) instead if camera-based visual cat identification is the feature you need — specifically, if you have two cats of similar weight and appearance that the weight scale cannot tell apart. Otherwise you are paying $100 for a camera whose best features sit behind a subscription.
Still comparing across brands rather than within Whisker’s lineup? Our guide to the best automatic litter boxes puts all four Litter-Robot models alongside PETKIT, Petlibro, and CATLINK on the same table.
Check current pricing before you buy. Litter-Robot bundle promotions change often, and every price in this comparison is dated 2026-09-19 in USD.
How We Researched This
- All specifications, prices, and accessory compatibility data in this article come from Whisker’s own product pages, its published model comparison chart, and its 4-vs-5 documentation, retrieved on 2026-09-19.
- We used Whisker’s structured product data to confirm base prices and variant pricing rather than relying on marketing pages, because the product pages sometimes show a promotional "as low as" figure.
- Where Whisker’s marketing copy and its specification block disagreed — such as the Litter-Robot 5’s interior globe height, quoted as both 17.5" and "up to 19"" — we published both and labeled the discrepancy rather than picking one.
- Review ratings and counts are manufacturer-hosted aggregates from Whisker’s product pages. We report them with their sample sizes because an aggregate built on 23 reviews and one built on 14,093 reviews are not comparable evidence.
- We did not test these machines. No statement in this article is a first-hand usage claim. Read more about how we research.
Sources
- https://www.litter-robot.com/litter-robot-5.html
- https://www.litter-robot.com/litter-robot-5-pro.html
- https://www.litter-robot.com/litter-robot-4.html
- https://www.litter-robot.com/litter-robot-evo.html
- https://www.litter-robot.com/litter-robot-iii-open-air-with-connect.html
- https://www.whisker.com/litter-robot-comparison-chart
- https://www.whisker.com/blog/litter-robot-4-vs-5
- https://www.whisker.com/litter-robot-5
- https://www.whisker.com/litter-robot-5-pro
- https://www.whisker.com/litter-robot-evo
- https://www.whisker.com/whisker-plus
- https://www.whisker.com/whisker-app
- https://www.litter-robot.com/litterhopper.html
- https://www.litter-robot.com/litter-robot-4-carpet-tray.html
- https://www.litter-robot.com/litter-robot-4-ramp.html
- https://www.litter-robot.com/litter-robot-4-backup-battery.html
- https://www.litter-robot.com/litter-robot-waste-drawer-liners.html
- https://www.litter-robot.com/litter-robot-4-carbon-filters.html
- https://www.litter-robot.com/odortrap.html
- https://www.litter-robot.com/litter-robot/accessories.html
- https://www.litter-robot.com/litter-robot-4-starter-bundle.html
- https://www.litter-robot.com/litter-robot-5-starter-bundle.html
- https://www.litter-robot.com/litter-robot-5-pro-starter-bundle.html
- https://www.litter-robot.com/litter-robot-evo-starter-bundle.html
- https://www.whisker.com/greatlitter
- https://www.litter-robot.com/support/