Whisker Litter-Robot 4 vs Whisker Litter-Robot EVO
Researched by Riley Hart · prices checked Oct 26, 2026
As of Oct 26, 2026, the Whisker Litter-Robot 4 costs $699 and the Whisker Litter-Robot EVO costs $599, so the Whisker Litter-Robot EVO is $100 cheaper. Pick the Whisker Litter-Robot 4 for one to four average size cats. Pick the Whisker Litter-Robot EVO for one or two average size cats in a small space.
- Cat weight
- 3 to 25 lb
- Max cats
- Up to 4
- Litter
- Clumping clay
- Waste drawer
- Sealed
A well tested globe box with a long track record and a large parts and support network, now $100 cheaper than the Litter-Robot 5. Owners of big cats over 25 lb, or anyone who wants urine vs stool detection, should look at the 5 instead.
Full Whisker Litter-Robot 4 review →- Cat weight
- 3 to 19 lb
- Max cats
- Up to 2 cats
- Litter
- Clay based clumping
- Waste drawer
- Sealed
The EVO is the cheapest way into a Litter-Robot and fits smaller rooms than the Litter-Robot 4 or 5. It is rated for only two cats up to 19 lb, so big cats and busy multi cat homes should look at the larger models. It needs a flat, hard floor to avoid position errors.
Full Whisker Litter-Robot EVO review →Side by side
| Whisker Litter-Robot 4 | Whisker Litter-Robot EVO | |
|---|---|---|
| Price | $699 | $599 |
| 3 year cost | $1,035 | $599 |
| Our score | Not scored yet | Not scored yet |
| Rank in Litter box | #16 | #15 |
| Status | on sale | on sale |
| Warranty | 1 year (WhiskerCare), extendable to 3 years; 90 day in home trial | 1 year, 3 years with WhiskerCare ($99); 90 day in home trial |
| Cat weight range | 3 to 25 lb (kittens under 3 lb need semi automatic mode) | 3 to 19 lb |
| Max cats | Up to 4 | Up to 2 cats (maker) |
| Waste drawer | Sealed drawer with carbon filter, as little as once every 8 days (maker claim) | Sealed, carbon filtered drawer, up to 7 days for one cat (maker) |
| Sensors | Laser and weight sensors, SmartScale cat weight tracking, SafeCat system | Weight sensors and SafeCat anti obstruction system; no entry motion sensors (Vetstreet) |
| App | Whisker app (2.4 GHz WiFi); free 7 day view, Whisker+ optional | Whisker app (iOS and Android), 2.4 GHz WiFi only; Whisker+ membership optional |
| Litter type | Clumping clay recommended; crystals only if they pass the screen; plant based and pellet litters not recommended | Clay based clumping litter; crystal, plant, paper and pellet litters not recommended |
| Size | 22 x 27 in footprint, 29.5 in tall, 15.75 x 15.75 in entry, 24 lb empty | 20.6 x 24.3 in footprint, 27.6 in tall, 14.85 in entry, 21.5 lb empty |
| Noise | No dB rating published; QuietSift motor | Marketed as nearly silent (QuietSift); no dB figure given |
| Best for | one to four average size cats | one or two average size cats in a small space |
| Skip if | your cat is over 25 lb | you have a cat over 19 lb or three or more cats |
Specs are maker claims unless a reviewer is named. Prices from the stores we link, checked daily.
What reviewers found
Whisker Litter-Robot 4
- Cats.com: Runner Up in the October 2026 roundup; reliable and well built, but the smaller litter bed may not suit large cats. Source
- The Irish Times: Quiet, no smells and a clean tray in a home test; sensors stopped the drum when a cat entered; app cat ID was less accurate for cats of similar size. Source
- CNN Underscored: Drawer needed emptying about once a week with two cats; quieter than the Litter-Robot 3; cats took about a week to adjust. Source
Whisker Litter-Robot EVO
- Vetstreet: A veterinarian used it for about two weeks in a multi cat home and praised odor control and automation, but said the Litter-Robot 5 Pro would have suited her household better. Source
- TechnoMEOW: Used for a couple of months with three or more cats; setup was quick, but a mat edge caused a position fault error and app disconnects were more frequent than on the Litter-Robot 4 until a firmware update. Source
Pros and cons
Whisker Litter-Robot 4
Pros
- Long track record and wide parts availability
- Laser plus weight sensing with SafeCat
- Free app weight tracking
- 90 day in home trial
Cons
- Smaller litter bed than the 5 series
- Fine grain clumping litter only, not tofu
- Early units had sensor complaints
- Bulky, needs a 22 x 27 in spot
Whisker Litter-Robot EVO
Pros
- Lowest priced current Litter-Robot
- Arrives almost fully assembled
- Sealed, carbon filtered waste drawer
- Free app tracks visits and cat weights
Cons
- Rated for only 2 cats, 3 to 19 lb
- Clumping clay litter only
- No nightlight or entry motion sensor
- Mat edges can trigger position fault errors
Questions buyers ask
Which is better, the Whisker Litter-Robot 4 or the Whisker Litter-Robot EVO?
Pick the Whisker Litter-Robot 4 for one to four average size cats. Pick the Whisker Litter-Robot EVO for one or two average size cats in a small space.
Which is cheaper?
The Whisker Litter-Robot EVO at $599, versus $699 for the Whisker Litter-Robot 4, checked Oct 26, 2026. Over 3 years with running costs: $1,035 vs $599.
What is the difference between the Litter-Robot 4 and the Litter-Robot EVO?
Cat weight range: 3 to 25 lb (kittens under 3 lb need semi automatic mode) on the Litter-Robot 4, 3 to 19 lb on the Litter-Robot EVO. Max cats: Up to 4 on the Litter-Robot 4, Up to 2 cats (maker) on the Litter-Robot EVO. Waste drawer: Sealed drawer with carbon filter, as little as once every 8 days (maker claim) on the Litter-Robot 4, Sealed, carbon filtered drawer, up to 7 days for one cat (maker) on the Litter-Robot EVO.
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All self cleaning litter boxes, ranked
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