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Whisker Litter-Robot 4

Model LR4-0301-00-US Updated October 1, 2026

The white Litter-Robot 4 from the front, an orange cat sitting in its round opening, the Whisker app on a phone beside itBuy the Litter-Robot 4 ($699 at Amazon, checked November 2, 2026) for 3 to 4 cats, or a cat over 19 lb (up to 25 lb). For one or two smaller cats, the Litter-Robot EVO costs $100 less. It sifts clumps into a sealed drawer after each visit. Whisker rates it for up to 4 cats of 3 to 25 lb.

  • Size: 22 × 27 in floor space, 29.5 in tall, 15.75 in opening
  • Empties: about every 8 days with one cat
  • Refills: $65–$130 a year for OdorTrap packs (Whisker’s store price, read November 2, 2026); about $895–$1,090 to own for 3 years
$699 at Amazon

Price as of November 2, 2026. The bare unit, white. Black, or a bundle with refills.

Not the right size? One or two cats, up to 19 lb: Litter-Robot EVO. 5 cats, or a cat over 25 lb (up to 30 lb): Litter-Robot 5. Litter-Robot 5 vs 4 vs EVO.

Shopping for one? Start with the best automatic litter box.

  • The white Litter-Robot 4 from the front, an orange cat sitting in its round opening, the Whisker app on a phone beside it
  • Whisker photo: an orange cat inside a Litter-Robot 4 in a kitchen, with Whisker's line that it sifts waste after each use
  • Whisker photo: a long-haired cat in the Litter-Robot 4 and a second cat beside it, with Whisker's line that one unit suits up to four cats
  • Whisker photo: the Whisker app's weekly cleaning-cycle chart next to a Litter-Robot 4 with a cat inside
  • Whisker photo: a tabby cat inside the Litter-Robot 4, marked 29.5 in tall and 22 in wide, with Whisker's 3 to 25 lb cat range
Photos from the Amazon listing we link.

Questions buyers ask

Litter-Robot 4 size, front and side, to scaleFront view: 22 inches wide and 29.5 inches tall, with a round opening 15.75 inches across. Side view: 27 inches deep, or 28.8 inches with the LitterHopper on the back. Drawn to scale.FrontSide15.75 inopening22 in wide29.5 in tall27 in deep28.8 in with LitterHopper
To scale, from Whisker’s figures. The shape is simplified; the opening’s place follows Whisker’s photos. Dashed: the LitterHopper’s extra depth.

How big is it?

It takes 22 × 27 in of floor and stands 29.5 in tall. It weighs 24 lb empty. The opening is 15.75 in across, and the inside is 16.5 in high (Whisker).

How big is it with the LitterHopper?

The LitterHopper adds litter by itself and fits only the Litter-Robot 4. With it on, the floor space is 22 × 28.8 in, 1.8 in deeper. Whisker gives no total height. It costs $129 from Whisker; we found it on no Amazon listing on September 30, 2026 (Whisker).

What is the weight limit? Can kittens use it?

Whisker rates it for cats of 3 to 25 lb, including Maine Coons. A kitten under 3 lb is too light for the sensors. For those, Whisker says to leave the unit off, wait about 7 minutes after use, then turn it on to run one clean cycle (Whisker).

How many cats, and how often do you empty it?

Up to 4 cats. Whisker says the drawer lasts up to 8 days with one cat. Its setup guide says to plan on once a week for one cat and twice a week for two (Whisker). Put in a new liner each time you empty it.

What litter does it use?

Clumping clay. It takes about 8–10 lb to fill. Do not use pine, paper or other pellet litter, or non-clumping litter. White or see-through crystal litter can fool the level sensor (Whisker). Which litter to buy, with prices.

Is it loud?

No. Cats.com measured about 37 dB while it cycled, about as loud as a whisper (Cats.com). You can set the cycle to start 3 to 30 minutes after your cat leaves.

What do refills cost a year?

Whisker says to change the OdorTrap pack and the carbon filter every 2–4 weeks. OdorTrap packs cost about $65–$130 a year at Whisker’s store price, $30 for 6. We read Whisker’s price on November 2, 2026 (Whisker). Whisker sells its carbon filters on whisker.com: 6 cost $30, about $65–$130 more a year (Whisker). Drawer liners are $12 for 10, one per emptying.

Do I need the app or Whisker+?

No subscription is needed. The free Whisker app shows 7 days of visits and each cat’s weight. Whisker+ adds up to 2 years of history for $7.99 a month or $79.90 a year, with a 30-day free trial (Whisker). The app needs 2.4 GHz WiFi; 5 GHz will not work.

What is the warranty?

1 year. Whisker sells a 3-year plan for $129. Whisker’s 90-day home trial is for units bought from Whisker; if you buy on Amazon, returns go through Amazon’s seller (Whisker).

Litter-Robot 4, 5 or EVO?

Pick by your cats: the lowest-priced model Whisker rates for them. Our lineup pages use the same rule. What changed in the 5.

Your catsPickPrice
One or two cats, up to 19 lbLitter-Robot EVO$599 Amazon
3 to 4 cats, or a cat over 19 lb (up to 25 lb)Litter-Robot 4 (this page)$699 Amazon
5 cats, or a cat over 25 lb (up to 30 lb)Litter-Robot 5$799 Whisker list
You want a camera to tell cats apartLitter-Robot 5 Pro$899 Whisker list

Whisker's numbers are the most it rates each box for. A house right at a limit, such as two cats in the EVO, is rated by Whisker, but every extra cat fills the drawer sooner than the one-cat figure. Amazon prices as of November 2, 2026.

What do the lights mean?
  • Solid blue: ready.
  • Flashing blue: the drawer is full.
  • Solid red: a cat was seen; the countdown to the clean cycle has started.
  • Solid yellow: paused in the middle of a cycle.
  • Flashing yellow WiFi light: in WiFi setup.
  • Solid purple: sleep mode.

From Whisker: Litter-Robot 4 setup guide and light codes. The full manual: Whisker: Litter-Robot 4 user manual.

What testers and owners report

We do not test units ourselves. These testers did, for months.

  • Odor: Cats.com’s testers smelled nothing unless the drawer was open (Cats.com).
  • Not every cat takes to it: some of Cats.com’s test cats would not use it (Cats.com). At Engadget, two of three cats kept using it (Engadget).
  • Room inside: the litter bed is about 14 in across, which Cats.com calls small for big cats (Cats.com).
  • Sensor errors: after a few months, TechnoMeow’s unit sometimes paused mid-cycle. The fix was to take it partly apart and clean the sensors (TechnoMeow). Engadget also saw missed sifts and litter on the floor (Engadget).
  • Owners: on Whisker’s site it averages 4.5 of 5 from more than 13,000 reviews (Whisker). Complaints on Cats.com include a unit that stopped turning after a month and urine getting under the tub (owner comments).
Every limit Whisker publishes (14), with sources
LimitWhisker figure, with its source
Catsup to 4 (Whisker)
Cat weight3 to 25 lb (Whisker)
Drawer lasts, one catup to 8 days (Whisker)
Opening15.75 in round (Whisker)
Floor space22 × 27 in (Whisker)
With LitterHopper22 × 28.8 in floor space (Whisker)
Height29.5 in (Whisker)
Inside height16.5 in (Whisker)
Weight, empty24 lb (Whisker)
Litterclumping clay (Whisker)
Cycle delay3 to 30 minutes after use (Whisker)
WiFi2.4 GHz only (Whisker)
Warranty1 year; 3 years for $129 (Whisker)
In the boxUnit, power supply, fence, 5 liners, 1 carbon filter (Whisker)

Recall check (US and Canada): none found, November 2, 2026.

Sources

Read October 1, 2026; Whisker’s OdorTrap page read November 2, 2026. Amazon prices and listings checked November 2, 2026. These are Whisker’s figures and named testers’ findings, not our tests. How we work.

All 13 sources
  1. Whisker: Litter-Robot 4 page
  2. Whisker: Litter-Robot 4 setup guide and light codes
  3. Whisker: Litter-Robot 4 user manual
  4. Whisker: Whisker+ page
  5. Whisker: LitterHopper page
  6. Whisker: carbon filters
  7. Whisker: waste drawer liners
  8. Whisker: LitterTrap mat
  9. Whisker: OdorTrap packs
  10. Cats.com: Litter-Robot 4 review (months of home testing)
  11. Cats.com: owner comments
  12. TechnoMeow: Litter-Robot 4 review
  13. Engadget: Litter-Robot 4 review

Next: Which Litter-Robot to buy · Litter-Robot 5 vs 4 vs EVO · Best automatic litter box · Best litter for the Litter-Robot 4 · PETKIT Purobot Ultra vs Litter-Robot 4 · Litter-Robot 4 vs PETKIT vs Neakasa

Whisker Litter-Robot 4Price as of November 2, 2026

$699 at Amazon