Litter-Robot 4 vs Evo

Quick answer. Disclosure: bestcatgear.com participates in the Amazon Services LLC Associates Program and may earn a commission from qualifying purchases, at no extra cost to you. Check the current price on Amazon. Choose the Litter-Robot 4 if you have three or four cats, a cat over 19 lb, or you want litter level sensing and an automatic night light. Choose the Litter-Robot EVO if you have one or two cats under 19 lb, you are short on floor space, or the box has to sit on carpet. Both are made by Whisker. Both listings say they work with any clumping litter and have the free Whisker app, a status display, weight identification and a drawer full indicator. The differences are in the table below, which comes from the listings we opened on 2026-10-17.

Side by side, as the listings state

Most rows come from the comparison table printed on the EVO listing, which compares the two boxes directly. Size and warranty come from each listing’s details table.

Spec	Litter-Robot 4	Litter-Robot EVO
Number of cats	Up to 4	Up to 2
Cat weight range	3 to 25 lb	3 to 19 lb
Interior headroom	16.5 inches	14.5 inches
Drawer capacity	Large	Medium
Litter level sensing	Yes	No
Automatic night light	Yes	No
Robot status display screen	Yes	Yes
Free Whisker app	Yes	Yes
Weight identification (SmartScale)	Yes	Yes
Drawer full indicator	Yes	Yes
Size (details table)	27 x 24.25 x 29.5 inches (overview table says 24 x 24 x 31)	24.3 x 20.6 x 27.6 inches
Weight	24 pounds	21.5 pounds
Warranty	WhiskerCare 1-Year Warranty	1 Year Manufacturer
Model number	LR4-0101-00-US	LRE-0301-00-US
Minimum cat weight for Automatic Mode	3 lb (1.4 kg)	3 lb (1.4 kg)
Surface	Scale most accurate on a firm surface, not carpet or uneven surfaces	Can be used on any surface, even carpet

Both listings say odor control comes from the automatic clean cycle plus carbon filters or optional OdorTrap Packs. Neither text we read states a noise level, a cycle time or the drawer size in liters.

Worked example: three households

• Three cats of 9, 11 and 13 lb. The EVO is listed for up to 2 cats, so it does not cover three. The Litter-Robot 4 is listed for up to 4. Each cat is inside the 3 to 25 lb range.
• One 22 lb cat. The EVO range stops at 19 lb, which is 3 lb short. The Litter-Robot 4 range goes to 25 lb, leaving 3 lb of margin. For a cat this size also compare the headroom: 16.5 inches against 14.5, a gap of 2 inches.
• Two 8 lb cats in a small flat. Both fit the weight limits. Using the details tables, the footprint is 27 x 24.25 inches (about 655 square inches) for the Litter-Robot 4, or 576 if the overview figure of 24 x 24 is right. The EVO is 24.3 x 20.6 inches, about 501 square inches. That is 75 to 154 square inches less floor, between 13% and 24% less than the Litter-Robot 4 depending on which of its two figures is correct.

The percentages: (655 – 501) / 655 is about 24%, and (576 – 501) / 576 is about 13%. Measure your space with the larger Litter-Robot 4 number until you can confirm the real one.

Choose by use case

• Three or four cats: Litter-Robot 4. The EVO is listed for two.
• A large cat, 20 lb or more: Litter-Robot 4. It is listed to 25 lb with 16.5 inches of headroom.
• Tight space: EVO. It is smaller in all three dimensions of the details tables, and the EVO listing says it has the same footprint as a traditional litter box. We cannot check that claim; the listed 24.3 x 20.6 inches is the number to measure against.
• Carpet: EVO. Its listing says any surface, even carpet. The Litter-Robot 4 listing says the scale is most accurate on a firm surface.
• Reminders when the litter runs low, and a light at night: Litter-Robot 4. The comparison table marks litter level sensing and the automatic night light as “no” on the EVO.
• A kitten under 3 lb: neither. Both listings set a 3 lb minimum for Automatic Mode.

Conflicts and gaps (not resolved)

• The Litter-Robot 4 listing gives two sizes: 27 x 24.25 x 29.5 inches in the details table and 24 x 24 x 31 inches in the overview table.
• The Litter-Robot 4 bullets mention a complimentary fence and an included step, but the search results show a separate black listing titled “with Step & Fence”. We cannot tell whether the white Robot Only listing includes them. The EVO listing text we read mentions neither.
• The comparison table is printed on the EVO listing, so it is Whisker’s own comparison. We did not find a second source for it.
• Neither listing gives noise, cycle time, power use or drawer size in liters.
• The comparison table shows white and black versions of both boxes. We opened the white Litter-Robot 4 and the black EVO listings; the tables list the same values for both colors.

The two products

Whisker Litter-Robot 4

The listing says the sifting process separates waste from clean litter, and you empty the waste drawer when it is full. The Whisker app shows waste and litter levels, health insights and your cat’s weight after each use. We cannot judge the health insights; for changes in weight or bathroom habits, ask your vet.

View the Litter-Robot 4 on Amazon

Whisker Litter-Robot EVO

The listing describes a compact design for apartments, bathrooms and tight corners, with weight-based cat identification, daily visit and cycle tracking and remote control through the app. It says the EVO suits first-time owners and one- or two-cat households.

View the Litter-Robot EVO on Amazon

FAQ

What is the main difference between the Litter-Robot 4 and the EVO?

Capacity. The Litter-Robot 4 is listed for up to 4 cats of 3 to 25 lb with a large drawer. The EVO is listed for up to 2 cats of 3 to 19 lb with a medium drawer.

Do both have the app?

Yes. The comparison table shows the free Whisker app, weight identification and the status display on both.

Which one is smaller?

The EVO. It is listed at 24.3 x 20.6 x 27.6 inches and 21.5 pounds, against 27 x 24.25 x 29.5 inches and 24 pounds for the Litter-Robot 4 in the details table.

Does the EVO have a night light or litter level sensing?

No. The comparison table marks both as absent on the EVO and present on the Litter-Robot 4.

Can I use either on carpet?

The EVO listing says it can be used on any surface, even carpet. The Litter-Robot 4 listing says only that the scale is most accurate on a firm surface and does not say whether the box itself can sit on carpet.

Do they have the same warranty?

Both are one year: WhiskerCare 1-Year Warranty on the Litter-Robot 4 title and 1 Year Manufacturer on the EVO details table. The listings do not explain how the two differ.