Walk into any pet store and you'll find litter boxes marketed as "standard" or "ideal for most cats." The uncomfortable truth: most of them aren't big enough. And a too-small litter box is one of the most common reasons cats start eliminating outside it.

The Rule of Thumb (Literally)

The minimum recommended size is 1.5 times your cat's body length from nose to base of tail. For an average adult cat (~46cm / 18 inches), that means a box at least 68cm (27 inches) long. Most retail boxes fall short at around 50cm (20 inches).

Signs Your Box Is Too Small

Watch for these behavioural clues: your cat turns around awkwardly inside the box, hangs their backend over the edge while digging, or immediately leaves after stepping inside without doing their business. These aren't quirky habits — they're stress signals.

Why It Matters More Than You'd Think

Cats in the wild are meticulous about where they eliminate. They need space to assume the correct posture, which requires room to brace themselves. When they can't, they associate the box with discomfort. That association builds over time and often manifests as avoidance behaviour that looks random but has a clear cause.

What Actually Works

Storage totes made from clear plastic are one of the best options — they're inexpensive, come in oversized dimensions, and have low sides that are easy for older cats to navigate. Under-bed storage boxes work well in apartments where space is tight. Check price on Chewy →

For multi-cat homes, the general rule is one box per cat plus one extra — but size matters just as much as quantity. A single enormous box can serve two cats better than two undersized ones, provided it's cleaned daily.

The Entry Height Trap

High-sided boxes solve the scatter problem but create an entry barrier, especially for kittens, senior cats, and cats with mobility issues. If you use a covered box or one with tall walls, consider cutting a low entrance — a simple U-shaped cut with a hobby knife transforms any plastic tote into an accessible option.

Making the Switch

If you're upgrading size, do it gradually. Place the new box next to the old one and let your cat discover it on their own terms. Most cats adapt quickly when the new box is genuinely more comfortable. View on Amazon →

The right litter box size won't fix every elimination issue — but it's one of the simplest and most overlooked fixes. Before you try new litter types, behavioural supplements, or vet visits, rule out the box itself. It might be the whole problem.