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By Jason Feng, Founder & Researcher. See how this review was researched.
Quick answer
The Litter-Robot 4 measures 22 inches wide, 27 inches deep and 29.5 inches tall, with a 15.75-inch globe opening and 16.5 inches of interior height. It weighs 24 lbs empty and lists at $699 in the US.
Those are the published numbers, and they are only half the answer. The number people get wrong is the height of the step your cat has to take, which Whisker’s own dimension drawings put at 12 inches to the entrance with a 6.9-inch step. Measure the floor, the doorway and the ceiling clearance before you measure anything else.
Table of contents
- The published dimensions
- How the Litter-Robot 4 compares to the 5 and the EVO
- What fits inside the globe
- Measurement 1: floor space and clearance
- Measurement 2: height and the opening bonnet
- Measurement 3: the step your cat takes
- The door frame and floor load question
- Carpet, outlets and the room itself
- The three-measurement checklist
- Our verdict
- How we researched this
- Sources
The published dimensions
Whisker publishes the Litter-Robot 4’s footprint and weight in the product page’s specification block, and the rest in the dimension drawings embedded in the same page. Read together, they give a complete picture.
Table 1. Litter-Robot 4 dimensions, from Whisker’s product page.
| Measurement | Figure | Where it came from |
|---|---|---|
| Footprint | 22" wide x 27" deep | Spec block |
| Exterior height | 29.5" | Dimension drawing |
| Globe opening width | 15.75" | Dimension drawing and FAQ |
| Interior globe height | 16.5" | Product FAQ |
| Height to the entrance | 12" | Side dimension drawing |
| Step height | 6.9" | Side dimension drawing |
| Weight, empty | 24 lbs | Spec block |
| Cat weight range | 3 to 25 lbs | Product FAQ |
| US list price | $699 | Product page |
| Power | 15 V DC | Spec block |
The dimensional drawings carry one footnote that matters for planning: the interior height depends on litter level, because the litter bed occupies the bottom of the globe. Fill the globe to the line and you reduce the headroom by design, not by accident.
Whisker’s own copy frames the footprint as the selling point, noting the Litter-Robot 4 has the same footprint as a traditional large litter pan and needs no elaborate installation planning. That is fair as far as it goes. A large covered pan is indeed about 22 by 27 inches on the floor. What the comparison leaves out is the 29.5-inch height and the step.
How the Litter-Robot 4 compares to the 5 and the EVO
The three current Litter-Robot models are close relatives with different footprints, and the difference decides which rooms they fit.
Table 2. Dimensions across the current Litter-Robot line, from Whisker’s product pages.
| Litter-Robot 5 / 5 Pro | Litter-Robot 4 | Litter-Robot EVO | |
|---|---|---|---|
| Footprint | 22" x 27" | 22" x 27" | 20.6" x 24.3" |
| Exterior height | 29.9" | 29.5" | 27.6" |
| Globe opening | 15.75" | 15.75" | 14.85" |
| Interior headroom | 17.5" | 16.5" | Not published |
| Weight, empty | 28.7 lbs | 24 lbs | 21.5 lbs |
| Cat weight range | 3 to 30 lbs | 3 to 25 lbs | 3 to 19 lbs |
| US list price | $799 | $699 | $599 |
| Carpet tray | Integrated | Sold separately | Integrated |
The 4 and the 5 share a footprint and an opening width, so a room that fits one fits the other with room to spare on the depth. The EVO is the outlier in every row: 25 percent smaller than the Litter-Robot 5 by Whisker’s own description, lighter by more than seven pounds, and rated for a smaller cat.
Two rows change how the machine behaves in a room rather than whether it fits. The Litter-Robot 4 does not have an integrated carpet tray, so carpeted floors need the separate accessory for accurate weight readings. And the cat weight rating tops out at 25 lbs on the 4 against 30 lbs on the 5, which matters for a large breed. If the cat is the constraint rather than the room, our guide to self-cleaning boxes for large cats works through the sizing.
For the full generation-by-generation breakdown, our Litter-Robot 5 vs 4 vs EVO comparison covers what changed between them.
What fits inside the globe
The exterior numbers tell you whether the machine fits the room. The interior numbers tell you whether the cat fits the machine, and Whisker publishes both.
The opening is 15.75 inches wide, and Whisker states the interior height is 16.5 inches on the Litter-Robot 4 and 17.5 inches on the 5. The company’s own guidance is that size and weight have little to do with whether a cat will acclimate, and the real test is whether the cat can enter the globe and turn around comfortably inside it.
That is a sound instinct and it is measurable. A cat needs approximately its own body length to turn in a cylinder, plus clearance for the head and the tail. A 15.75-inch opening accommodates a very large domestic cat, which is why the Litter-Robot 4 is rated to 25 lbs. What it does not do is leave a large cat much margin once the litter bed is in place.
The interior numbers inherit one moving part, and it is worth flagging here because it drives fault behavior later. The globe liner holds a weight that the machine uses to measure the litter bed, and litter level affects both headroom and calibration. If you have seen light codes you cannot place, the Litter-Robot flashing yellow light guide explains what each pattern means and in what order to check them.
Measurement 1: floor space and clearance
Start on the floor, because a machine that does not fit the spot never gets installed.
The published footprint is 22 by 27 inches, and it is asymmetric: the 27-inch figure is the depth, front to back. That orientation matters in a narrow closet or a hallway, where you may have width but not depth.
Add the working clearances on top of the footprint rather than inside it. Whisker recommends placing the unit on a firm surface about an inch away from the wall. The waste drawer pulls out from the front, so you need a clear path in front of the machine, and the bonnet opens upward, which is Measurement 2.
Do the arithmetic with the accessories rather than the bare machine. The Litter-Robot 4 supports the LitterHopper, an automatic litter dispenser that mounts on the machine and changes both the silhouette and the height. If you plan to add it, measure with it in place. Whisker states the LitterHopper is compatible with the 4, the 5 and the 5 Pro, and that the Litter-Robot Cabinet and Credenza are also compatible with it.
Finally, check the floor you are placing it on. Whisker’s own FAQ warns against soft, unstable flooring for machines in this class generally, and for the Litter-Robot 4 specifically recommends the Carpet Tray if the carpet is 3mm or thicker or the floor is uneven. The tray is an accessory, not a requirement, but its absence shows up as inaccurate weight readings rather than an obvious failure.
Measurement 2: height and the opening bonnet
Height is where the Litter-Robot 4 surprises people, because 29.5 inches is taller than most furniture and most litter areas.
Put a tape against the spot and account for three separate clearances.
The resting height is 29.5 inches. That is the machine standing still, bonnet closed.
The working height is higher, because the bonnet opens upward to give access to the globe and the carbon filter. The carbon filter sits on the lower exterior of the globe, directly above the waste drawer, and Whisker’s instructions have you open the bonnet to reach it. If there is a shelf, a cabinet top or a counter above the spot, the opening arc is what has to clear it.
The maintenance height is higher again at the moment you lift the globe off the base, which is a step in the deep clean. If you are planning to put the machine under furniture, measure the lift.
Under-furniture placement has a second constraint beyond clearance: ventilation. An enclosed space around the machine reduces airflow, and the enclosure question is covered in our litter box enclosure buying guide.
Measurement 3: the step your cat takes
This is the measurement owners skip, and it is the one that decides whether the cat uses the machine at all.
Whisker’s dimension drawing puts the entrance 12 inches above the floor, with a 6.9-inch step in front of it. So the cat’s approach is a step up to a platform and then a second rise to the entry lip, not a flat walk-in.
For a young, mobile cat that is nothing. For an older cat it is a real consideration, and it is the same reason the ASPCA cautions that geriatric cats, overweight cats and cats with physical limitations may struggle with boxes that need a climb. Whisker sells a Ramp as an accessory for exactly this reason, and the ramp’s own dimensions add to the footprint in front of the machine.
Measure the approach like this. Put a tape at the machine’s entry height in the position you plan to install it, and watch your cat take the step you expect. If the cat already jumps onto furniture without hesitation, the entry height is unlikely to be the problem. If the cat has slowed down, add the ramp and measure again with it in place. Integration of the machine with the room’s traffic is also a factor, and our multi-cat placement guide covers distance from food, water and noise.
One more cat-side number: the machine is rated from 3 to 25 lbs. Whisker notes kittens at 3 lbs and up can use it in automatic mode, and recommends semi-automatic operation for kittens below that, cycling the machine manually about seven minutes after use so the kitten is never inside a moving globe.
The door frame and floor load question
Two measurements people forget until the box is on the doorstep.
The door frame. A 27-inch-deep, 22-inch-wide box in a shipping carton is considerably larger than the machine, and a carton on its side has to pass through the delivery path: front door, stairwell, hallway, the turn at the end of the landing. Check the narrowest horizontal opening in the route, including the carton’s depth, because the constraint is usually a hallway corner rather than a door.
The floor load. The machine is 24 lbs empty. Litter at Whisker’s recommended fill adds roughly 8 to 10 lbs, and a 20-pound Maine Coon on top brings the assembly to somewhere near 55 lbs over a footprint of about 594 square inches. That is a light distributed load, well inside what any residential floor carries, and the real risk is not deflection but presentation: on a soft floor the machine can settle unevenly, which is exactly the condition Whisker’s FAQ flags for the weight sensors. Firm and level is the requirement, and a carpet tray or a board underneath is the fix if the floor is not.
Carpet, outlets and the room itself
Three room conditions change how the Litter-Robot 4 behaves, and all three come from the manufacturer.
Carpet. The Litter-Robot 4 lacks the integrated carpet tray the 5 and EVO have. Whisker states that SmartScale weight readings are most accurate on a firm surface, and that carpet at 3mm or thicker or uneven flooring is the case where the separate Carpet Tray helps. The tray is described as not required for the unit to function.
Moisture. Whisker recommends avoiding the bathroom for placement because moisture can damage the components. That rules out a common location for a lot of households and pushes the machine toward a hallway, laundry room or closet.
Power. The unit runs on 15 V DC and ships with an adapter, and Whisker advises against running a Litter-Robot on battery power as a primary source. The cord length to the nearest outlet becomes a placement constraint, since an extension cord across a walkway is a trip hazard and a chew temptation.
The operating cost beyond the machine is also a placement consideration if you are weighing a cheaper spot far from an outlet. The consumables arithmetic is in our Litter-Robot cost of ownership breakdown.
The three-measurement checklist
Run this before you order, in this order.
- Floor. Tape the 22 by 27 inch footprint in the spot, in the correct orientation, and add about an inch to the wall. Confirm the waste drawer can pull out with room to stand in front of it.
- Height. Measure from the floor to whatever is overhead. The machine stands 29.5 inches tall, the bonnet opens above that, and lifting the globe for a deep clean needs more height again.
- Cat entry. Mark 12 inches on the wall where the entrance will sit and watch the cat approach it. Add the ramp to the footprint if the step is a problem.
- Route. Measure the narrowest point between the front door and the spot, and check it against the shipping carton rather than the machine.
- Surfaces. Note the flooring type, the nearest outlet and any moisture source. Carpet at 3mm or more on the Litter-Robot 4 calls for the Carpet Tray; a bathroom is the wrong room.
- Accessories. If a LitterHopper is planned, measure with it installed, since it changes the profile.
Six checks, ten minutes, and they answer the questions that a spec table cannot.
Our verdict
Buy the Litter-Robot 4 if the footprint and the entry height suit your cat and your room. At 22 by 27 inches it occupies the same floor as a large traditional pan, and Whisker’s own drawings put the step at 6.9 inches up to a 12-inch entry. For a young, mobile cat, that geometry is fine.
Our guidance for the two groups who should measure hardest. Large cats: the Litter-Robot 4 is rated to 25 lbs and leaves less interior headroom than the Litter-Robot 5’s 17.5 inches, so a very large breed is better served by the newer model. Carpeted rooms: budget the Carpet Tray at the same time as the machine, because without it the weight-based readings are the first thing to misbehave.
What we would not do is order on the footprint alone. The two numbers that decide whether the machine gets used are the height above it and the step in front of it, and neither appears in the short specification list.
How we researched this
- Manufacturer dimensions, read from the source. Every measurement in this article was taken from Whisker’s Litter-Robot 4 product page, its dimension drawings and its product and support FAQ blocks, fetched through a US egress so the model listing and pricing match the American storefront. Comparative figures for the Litter-Robot 5 and EVO come from the same manufacturer.
- Placement and surface guidance from vendor documentation. The wall clearance, the bathroom warning, the carpet-tray condition, the litter fill guidance and the kitten mode instructions are Whisker’s own published advice, not inference.
- Veterinary behavior guidance for the cat-side caveat. The ASPCA’s litter box guidance supplied the caution about geriatric, overweight and mobility-limited cats and high-entry boxes.
- Research-based and source-attributed. This is a research-based review. Specifications come from manufacturer documentation, with owner-reported failure patterns aggregated across public reviews and community threads.
- Totals labeled as arithmetic. The floor-load figure is our own estimate from published weights, presented as an estimate rather than a vendor claim.
See our full methodology page for how we handle sourcing and affiliations.
Sources
- https://www.litter-robot.com/litter-robot-4.html
- https://www.litter-robot.com/litter-robot-5.html
- https://www.litter-robot.com/faq.html
- https://www.litter-robot.com/support/article/litter-robot-4-dimensions-comparison-to-litter-robot-3/
- https://www.litter-robot.com/support/article/litter-robot-4-deep-cleaning/
- https://www.litter-robot.com/support/article/litter-robot-4-use-and-care/
- https://www.litter-robot.com/support/article/litter-robot-4-ongoing-maintenance/
- https://www.litter-robot.com/litter-robot-4-carpet-tray.html
- https://www.litter-robot.com/support/
- https://www.aspca.org/pet-care/general-pet-care/addressing-litter-box-problems