CompareMyPetsLitter-Robot 4 Review 2026
The gold standard of self-cleaning litter boxes.
What we like
- Fully automatic self-cleaning
- OdorTrap technology
- App tracks visits and each cat's weight
- Works for cats 3–25 lbs (automatic mode)
- Sealed drawer: may only need emptying about every 8 days (Whisker)
Things to consider
- Premium price tag
- Large footprint — not for small spaces
- Some cats take time to adjust
Litter-Robot 4 is Whisker's rotating, self-cleaning litter box. After a cat leaves, the globe sifts clumps into a sealed waste drawer in the base and levels a fresh litter bed. The figures below come from Whisker's own product page, support FAQ and user manual. We have not tested the unit ourselves.
Maker specifications
| Size (H x W x D, assembled) | 29.5" x 22" x 27" |
|---|---|
| Weight (empty) | 24 lb |
| Entryway | 15.75" x 15.75" |
| Inside the globe | 15–17" high (depends on litter level) x 19" wide x 18" deep |
| Litter bed | 14" x 14" |
| Floor to entryway | 12" (an optional step is included) |
| Waste drawer | 5.5" x 13.5" x 9.25" |
| Litter fill | About 8–10 lb of clumping litter (about 1 gallon) to the MAX fill line |
| Cats | Up to 4 cats; automatic mode for cats of 3 lb and up |
| Sensors | Three laser 'curtain' sensors in the bezel plus a weight scale (SmartScale) in the base |
| Wi-Fi | 2.4 GHz only (5 GHz not supported) |
| Power | 15 V DC with the included power supply |
Whisker says you may only need to empty the waste drawer about once every 8 days, depending on how many cats you have and their size.
Who it suits
- Homes with up to four cats that want to replace several boxes with one (Whisker rates one unit for up to 4 cats).
- Large cats: Whisker says there is no weight limit and lists breeds like Maine Coons inside the 15.75" entryway and 15–17" interior height.
- Owners who want usage and weight data: the Whisker app shows a 7-day view of visits and each cat's weight, with longer history on the optional Whisker+ membership.
- Skittish cats that need time: the cleaning cycle waits after a cat exits, and the delay can be extended up to 30 minutes.
Who should skip it
- Kittens under 3 lb, unless you run it in supervised semi-automatic mode (Whisker's own instruction) until they are heavier.
- Tight spaces: the assembled unit is 29.5" tall on a 22" x 27" footprint, and Whisker says it should not touch a wall or sit in a corner for accurate weighing.
- Homes that use plant-based, pellet, newspaper or non-clumping litter. Whisker says those usually don't sift; clumping clay works best, and white or translucent crystals can confuse the drawer-full sensor.
- Thick carpet: SmartScale is most accurate on a hard, level floor. Whisker sells a Carpet Tray for carpet over 3 mm.
- Homes with only a 5 GHz Wi-Fi network.
How the cleaning cycle works
Laser curtain sensors and the base weight scale detect when a cat enters and leaves. A countdown starts after the cat exits; then the globe rotates, sifts waste through the screen into the drawer, and returns to level. If extra weight is detected during a cycle, the globe stops and resumes 15 seconds after the weight is gone (Whisker manual).
Ongoing upkeep
Replace the drawer liner each time you empty the drawer. Whisker suggests changing the carbon filter and optional OdorTrap packs every 2–4 weeks. Keep the globe filled with clumping litter to the MAX line, and press Reset to re-zero the scale after anything changes the unit's weight.
Returns and warranty (from Whisker)
Whisker offers a 90-day in-home trial on units bought from Whisker.com or Litter-Robot.com; units bought elsewhere follow that retailer's return policy. Whisker's WhiskerCare warranty covers the unit for 1 year, with a 3-year extended plan included in some bundles or sold separately.
Frequently asked questions
Can kittens use Litter-Robot 4?
Yes, but only in automatic mode once they weigh at least 3 lb. Below that, Whisker recommends semi-automatic mode: leave the unit off, wait about 7 minutes after the kitten uses it, power it on for one clean cycle, then switch it off again.
Does Litter-Robot 4 have a weight limit?
Whisker says no. It is designed for cats of 3–25 lb, and the 15.75" x 15.75" entryway and 15–17" interior height fit almost any domestic cat.
What litter does it need?
Standard-weight clumping clay litter is Whisker's recommendation. Some silica crystals work if they pass through the screen, but white or translucent litter can affect the litter-level and drawer-full readings. Plant-based, pellet, newspaper and non-clumping litters usually don't work.
Will it connect to 5 GHz Wi-Fi?
No. Whisker says Litter-Robot 4 needs a 2.4 GHz Wi-Fi network.
How often do I empty the drawer?
It depends on how many cats you have and their size. Whisker says it can be as little as about once every 8 days.
Can I put it on carpet?
Yes, but the weight readings are less accurate on carpet. Whisker's Carpet Tray improves this on carpet 3 mm or thicker; it isn't required for the unit to work.
Related on CompareMyPets
- Smart litter boxes compared
- Best automatic litter box: full buying guide
- Litter-Robot 4 vs PetSafe ScoopFree
- PetSafe ScoopFree Ultra
Sources (checked October 25, 2026): Whisker: Litter-Robot 4 product page · Whisker: Litter-Robot 4 FAQ · Whisker: Litter-Robot 4 user manual (PDF) · Whisker: Litter-Robot 4 safety features