How many litter trays do I need for two cats?

Two cats need three litter trays. The standard rule, used by vets and feline behaviourists, is one litter tray per cat plus one extra, placed in different locations around the home. It sounds excessive until you understand why cats avoid shared trays, and it is the single most effective fix for toileting outside the box in a multi-cat household. This guide explains the rule, where to put the trays, what counts as a separate tray, and when you can bend it.

The one-per-cat-plus-one rule

Number of cats	Litter trays needed	Minimum separate locations
1	2	2
2	3	2–3
3	4	3
4	5	3–4

Even a single cat benefits from two trays: one is always clean, and some cats prefer to urinate in one place and defecate in another.

Why two cats can't just share one litter tray

Cats are not pack animals. They tolerate each other, but toileting is a vulnerable moment and the tray is a resource worth guarding. Four problems come up when two cats share one tray.

• Guarding. The more confident cat sits near the tray. The other cat waits, holds on, and eventually goes behind the sofa instead. You rarely see this happen; you only see the result.
• Dirt. Two cats fill a tray twice as fast. Many cats refuse a tray that already has a clump in it, so the second user of the morning goes elsewhere.
• Scent. Each cat's waste carries scent. A tray that smells strongly of another cat can be enough to put a sensitive cat off.
• Ambush points. If the only tray is in a dead-end, a cat inside has no escape route. Nervous cats learn to avoid it.

A third tray breaks every one of these. There is always a clean option, always one that isn't being guarded, and always a second route.

Where to put the litter trays

Three trays lined up in a row in the utility room count as one. Cats see a cluster as a single toileting site, and the guarding cat can control all of them from one spot. Spread them out.

1. Different rooms, or at least different ends of a large room. Upstairs and downstairs is ideal in a house.
2. Quiet, but not isolated. A corner of a spare bedroom, the end of a landing, beside a bath. Not next to the washing machine, boiler or a door that bangs.
3. Away from food and water. Cats won't eat where they toilet. Keep bowls and water fountains in a separate area.
4. With two ways out. Avoid cupboards and tight alcoves. An open tray in the open corner of a room is safer, from the cat's point of view, than a hooded tray in a cupboard.
5. Reachable by the cat that needs it most. An older cat with stiff joints needs a low-entry tray on the floor they spend most time on, not one up two flights of stairs.

Tray type and size for two cats

Each tray should be at least one and a half times the length of the biggest cat using it, measured nose to tail base. For most adult cats that means a tray of 55–60cm or more; large breeds need 65cm plus. Depth of 12–15cm suits most cats, deeper for diggers.

Mixing types is fine. If one cat likes a hooded tray and the other wants it open, provide both. If unsure, start with open trays: more cats accept them, they're easier to monitor, and they don't trap smell. Our cat litter boxes and trays are listed by internal length, depth and entry height so you can match each tray to each cat.

Keep the same litter in every tray. Changing litter type between trays creates another reason for a cat to avoid one.

Does a self-cleaning litter box count as more than one?

No. An automatic box is one tray that's clean more often, which helps with dirt but not guarding, scent or location. For two cats, the practical setup is one self-cleaning litter box plus two manual trays in other rooms. Always keep a manual tray available in case the unit is mid-cycle or a cat hasn't accepted it.

Keeping three trays manageable

• Scoop every tray once a day minimum, twice if you can. It takes about a minute per tray.
• Full litter change and wash once a week for clumping litter, more often for non-clumping.
• Use a litter mat under each tray to catch tracking.
• Keep a scoop and lined bin by each tray.
• Choose stainless steel if odour from the tray itself is a problem. See our guide to stainless steel vs plastic litter trays.

When can you bend the rule?

Two bonded cats that have shared one tray for years without an accident can usually carry on, though a second tray costs little and prevents a problem. Cats with outdoor access that mostly toilet outside may need only one indoor tray each. In a studio flat where three trays won't fit, two trays at opposite ends of the room, scooped twice a day, is the compromise.

If either cat has started toileting outside the box, don't bend the rule. Add the third tray first, then see your vet, because urinary infections and cystitis are common causes and look identical to a behaviour problem from the outside.

Quick checklist

• One tray per cat plus one
• Trays in separate locations, not in a row
• Each tray at least 1.5 times the biggest cat's length
• Away from food, water and noisy appliances
• Two ways out of every tray position
• Same litter in every tray
• Scooped daily, washed weekly

Litter tray FAQs

Can two cats share one litter tray?

Some bonded pairs manage, but it's the most common cause of toileting outside the box in two-cat homes. Three trays in separate places is the safe setup.

How many litter trays for three cats?

Four, in at least three different locations.

Can I put all the litter trays in one room?

Cats treat a cluster of trays as one site, so you lose most of the benefit. Spread them across rooms or at least opposite ends of a large room.

Why does one cat use the tray and the other doesn't?

Usually the second cat is being blocked from it or finds it too dirty. Add a tray in a different room, then see your vet if accidents continue.

Setting up for two cats? Browse our litter boxes and trays by size, depth and entry height and pick three that suit each cat and each room. Free tracked UK delivery on every order and 30-day returns on unused items.