Litter-Robot 4 vs 5 vs EVO: Which One Should You Buy?

Quick answer: Buy the Litter-Robot EVO if you have one or two cats under 19 lb and limited space. Buy the Litter-Robot 4 for 2–4 cats or cats up to 25 lb; it’s the proven middle option and the one sold on Amazon. Buy the Litter-Robot 5 only if you want WasteID health tracking, have up to 5 cats, or a cat over 25 lb.

The three models use the same basic idea: a rotating globe sifts clumps into a sealed drawer after every visit. What changes is how many cats each one is rated for, how big they are, how much they sense, and how much they cost. All specs below come from Whisker’s own spec pages and comparison chart, checked on November 2, 2026.

We may earn a commission if you buy through links on this page, at no extra cost to you. We have not tested these litter boxes hands-on. This comparison is based on the manufacturer’s published specifications, retailer listings and published owner feedback, all linked in the sources.

Key takeaways

• Cats and weight decide most of it: EVO = up to 2 cats, 3–19 lb. LR4 = up to 4 cats, 3–25 lb. LR5 = up to 5 cats, 3–30 lb.
• The EVO is the space saver: 20.6 × 24.3 in footprint and 27.6 in tall, versus 22 × 27 in for the LR4 and LR5.
• WasteID (urine vs stool) is LR5-only. It’s the main reason to pay more than the LR4.
• Where to buy: the LR4 and EVO were on Amazon.com on Nov 2, 2026. The LR5 and 5 Pro were Whisker-only.
• The app is free on all models. Whisker+ is an optional subscription for longer history.

Litter-Robot 4 vs 5 vs EVO at a Glance

Spec (Whisker, Nov 2026)	Litter-Robot EVO	Litter-Robot 4	Litter-Robot 5	Litter-Robot 5 Pro
List price (“starting at”)	$599	$699	$799	$999
Cats supported	Up to 2	Up to 4	Up to 5	Up to 5
Cat weight range	3–19 lb	3–25 lb	3–30 lb	3–30 lb
Footprint	20.6 × 24.3 in	22 × 27 in	22 × 27 in	22 × 27 in
Height	27.6 in	29.5 in	29.9 in	29.9 in
Entryway	14.85 × 14.85 in	15.75 × 15.75 in	15.75 × 15.75 in	15.75 × 15.75 in
Interior height	14.5 in	16.5 in	17.5 in	17.5 in
Unit weight (empty)	21.5 lb	24 lb	28.7 lb	29.6 lb
Drawer, 1 cat (approx.)	~7 days	~8 days	~10 days	~10 days
Waste-level sensing	Notifies only when full	Monitors any level	Monitors any level	Monitors any level
WasteID (pee vs poop)	No	No	Yes	Yes
Cameras	No	No	No	Dual integrated
LitterHopper compatible	No	Yes	Not confirmed	Not confirmed
Carpet	Built-in carpet tray	Carpet Tray add-on recommended for weight accuracy	Hard floor or carpet	Hard floor or carpet
Sold new on Amazon (Nov 2, 2026)	Yes	Yes	Not found	Not found

Prices are Whisker’s list prices on the date above. Retailers and Whisker run frequent bundles and holiday promotions, so check the current price before buying. Our Black Friday cat deals guide explains how to tell a real discount from a crossed-out list price.

Litter-Robot EVO vs 4: Size, Cats and Sensors

The EVO is Whisker’s compact, entry-level model. Whisker describes it as “a more compact version of Litter-Robot 4” for households with one or two cats.

Where the EVO wins:

• Smaller footprint and lower height. It is about 1.4 inches narrower and 2.7 inches shallower than the LR4, and almost 2 inches shorter. That matters in a bathroom corner, a closet or an apartment. If you’re already squeezing a cat tree into a small home, our guide to small-apartment vertical space has more ideas.
• Any floor. Whisker lists a built-in carpet tray, so it can sit on carpet without an add-on.
• Price. It’s $100 less than the LR4 at list price.

Where the LR4 wins:

• More cats and bigger cats. Up to 4 cats and 25 lb, versus 2 cats and 19 lb.
• More room inside. The interior is 16.5 inches tall versus 14.5, and the entryway is 15.75 inches versus 14.85. Whisker itself suggests the LR4 or LR5 for “an especially large or tall cat.”
• Better sensing. The LR4 monitors litter level and waste level continuously. The EVO only tells you when the drawer is full.
• Accessories. The LR4 works with the LitterHopper auto-refill accessory; the EVO does not.
• Night light. Amazon’s comparison table on the Whisker listings marks an automatic night light for the LR4, not the EVO.

Verdict: for a single cat of average size in a small home, the EVO covers what matters. Once you have a second large cat, a third cat, or a cat near 19 lb, the LR4 is the safer long-term buy.

Litter-Robot 4 vs 5: Is WasteID Worth $100?

Whisker lists these Litter-Robot 5 upgrades over the LR4:

• WasteID, which distinguishes urine from feces after each visit.
• A slightly larger globe (17.5 in interior height vs 16.5 in).
• A larger, better-distributed waste drawer: about 10 days for one cat vs about 8.
• An LCD display.
• A wider weight range (3–30 lb) and up to 5 cats.

The footprint is identical (22 × 27 in), so the LR5 doesn’t need more floor space.

Why WasteID can matter

Changes in how often a cat urinates or defecates can be an early sign of a health problem. Examples are urinary issues, kidney disease and diabetes. An app that logs pee and poop separately can make a change visible sooner than you’d notice by looking at a self-cleaning box, which hides the evidence by design. It doesn’t diagnose anything. Think of it as a prompt to call your vet sooner. If your cat has a chronic condition your vet already monitors, that data may be worth the extra $100.

If your cats are young and healthy, the LR4 already logs visits and weight per cat in the free app. For many homes that’s enough. Our guide to whether your cat is bored, lonely or sick covers other behavior changes worth watching.

Litter-Robot 5 vs 5 Pro

The 5 Pro is the same size with the same WasteID and limits. It adds an integrated dual camera system. Per Whisker, basic camera features are free in the app: 5 minutes of live streaming per day and recorded events. AI facial recognition, unlimited streaming and more storage need a Whisker+ membership. One year of Whisker+ is included when you buy the Pro. Whisker’s chart lists the Pro at $999.

Verdict: the LR4 is the value pick for most multi-cat homes. Choose the LR5 for health tracking, five cats, or cats over 25 lb. Choose the 5 Pro only if seeing which cat used the box is worth $200 more than the LR5.

The Litter-Robot 5 and 5 Pro were sold on Whisker’s site when we checked, not new on Amazon.

Running Costs: Liners, Filters, Litter and Subscriptions

The box is only part of the cost. Plan for:

• Waste drawer liners. Whisker says to replace the liner each time you empty the drawer. How often depends on how many cats you have, so multiply the “days per drawer” figure by your cat count.
• Carbon filter and OdorTrap packs. For the LR4, Whisker recommends replacing them every 2–4 weeks for best odor control.
• Litter. Whisker recommends a standard-weight clumping clay litter. Plant-based, non-clumping, newspaper and wood-pellet litters typically don’t sift properly. White or translucent crystal litter can affect the EVO’s sensors. You top up litter as clumps are removed, so you still buy litter, just less often than full changes.
• Whisker+ (optional). Every model includes a free 7-day history in the app. Whisker+ adds up to 2 years of history, trend reports and, on the Pro, AI recognition.
• Wi-Fi. The LR4 and LR5 require a 2.4 GHz network; 5 GHz isn’t supported.

What Owners and Reviewers Report

We didn’t test these units, so here is what published feedback says, and where it comes from:

• Wirecutter’s automatic litter box guide named the Litter-Robot 4 its top pick when we checked in November 2026. It also flagged finicky sensors and expensive consumables as drawbacks.
• Amazon’s review summary for the LR4 (275 ratings when we checked) says buyers praise build quality, easy cleaning and odor reduction. Durability and value got mixed feedback. Several reviewers mention sensors that need regular cleaning, or a weight scale that took time to work reliably.
• The EVO is newer and had only a few dozen ratings per color on Amazon. Its summary notes cats taking to it well and mixed reports on reliability. That’s too small a sample to call it either way.

The common thread is that sensors need cleaning and consumables add up. Both apply to every model.

Who Should Buy Which

If you…	Buy
Have 1 cat (or 2 small/average cats) and a tight space	EVO
Want the cheapest Litter-Robot that still fits a large cat up to 25 lb	Litter-Robot 4
Have 3–4 cats	Litter-Robot 4
Have 5 cats, or a cat over 25 lb (big Maine Coon)	Litter-Robot 5
Manage a cat’s urinary, kidney or diabetes condition with your vet	Litter-Robot 5 (WasteID)
Need to know which cat used the box, on camera	Litter-Robot 5 Pro
Want to buy on Amazon with Amazon’s holiday return window	EVO or Litter-Robot 4

Bringing home a new kitten? Whisker’s automatic mode needs each cat to weigh at least 3 lb, so a very young kitten will need a regular box first. Our new kitten checklist covers the basic setup.

Neither? Consider a Cheaper Self-Cleaning Box

A Litter-Robot is a $600–$1,000 purchase. If that’s more than you want to spend, or you aren’t sure your cat will accept a moving box, try a simpler rake-style model first. The PetSafe ScoopFree Clumping works with regular clumping litter and doesn’t need proprietary trays.

Whichever box you choose, introduce it slowly. Set it next to the old box, leave it switched off for the first few days, and only remove the old box once your cat is using the new one reliably. Cats under stress often show it through litter box changes. If your cat starts acting out, our guide to why cats destroy things helps you rule out boredom and stress.

How We Compared

• Specs come only from Whisker’s comparison chart and product pages, checked November 2, 2026. Where a spec wasn’t published for a model, we say so instead of guessing.
• Prices are Whisker’s list prices on that date, plus Amazon’s listed price for the LR4 ($699) and EVO ($599) on the same day. Both change often.
• Owner feedback is summarized from public sources linked above. We don’t invent reviews or ratings.
• What we did not do: we have not tested these units hands-on. When we do, we’ll say so clearly on this page.

Shopping for a cat lover instead? A Litter-Robot is one of the big-ticket ideas in our gifts for cat lovers guide.