What kind of cat litter do you use in an automatic litter box?
Your automatic litter box does the dirty work, but the type of litter you use determines how well it works. The wrong type of litter means clumps that fall apart in the sifter, lingering odors, and a waste bin that fills up faster. In this guide, we’ll explain the different types of litter available, which ones work and which ones don’t in a self-cleaning litter box, and how to choose the right one for your cat.
The only strict requirement: it must form clumps
An automatic litter box works with a sieve: after each use, the drum rotates and sifts the solid waste out of the clean litter. This only works if the urine forms a solid clump that rolls out of the sieve in one piece. If the clump falls apart, wet bits remain in the clean litter, and eventually you’ll just start to smell it.
This is what a clump should look like: firm and compact, so it rolls right out of the sieve in one go. Everything in this guide revolves around that one question: Does it clump well?
The four types of filling along the measuring stick
1. Bentonite (clay granules): the clumping champion
Bentonite is a natural clay that quickly absorbs moisture and forms a hard clump. That’s why it’s the global standard for automatic litter boxes. Be sure to check the quality: cheap bentonite creates more dust and clumps less effectively.
2. Plant-based (tofu and other fibers): light and clean
A filling made from tofu and plant fibers clumps well, weighs less, and is a natural choice. Many cats also find the soft kibble pleasant on their paws. Be sure to choose a variety that’s specifically designed to clump quickly, as that’s where the difference between brands lies.
3. Silica (crystals): unsuitable
Silica crystals absorb urine without clumping. This works fine in a regular litter box, but it’s useless in a sifting litter box: there’s nothing to sift out. Do not use in an automatic litter box.
4. Wood pellets and paper: usually unsuitable
When wood pellets come into contact with moisture, they break down into sawdust instead of forming a clump. A screen can’t process that either. There are types of wood that do form clumps, but be sure to check carefully whether the clump is firm enough.
Other things to keep in mind
In addition to clumping power, three things make a difference in practice. Dust: low-dust litter is better for your cat’s and your respiratory systems, and keeps the litter box and the drum cleaner on the inside. Good to know: the Poopy exclusively with weight sensors on the bottom, so dust can never interfere with its operation. Litter boxes that rely on infrared sensors are more susceptible to this. Grain size: Very fine grains stick to paws and spread throughout the house (tracking). Odor control: Good litter traps odors inside the clumps instead of masking them with perfume, because cats don’t like that.
Poopy Two Fillings
We developed our litter for our own automatic litter boxes, but it works in any litter box. There are two varieties based on the same principle: firm clumps, minimal dust.
Fusion is our plant-based filler made from tofu and cassava: it clumps quickly, contains natural ingredients, and is easy to use. Six bags cost €59.95.
Mineral is the clay version: 98% pure bentonite with the Triple Fresh System for odor control. 4 bags cost €31.95.
No more lugging things around or forgetting to order? With Poopy Essentials , your refills arrive automatically, with a discount and free shipping. You choose the frequency yourself and can pause your subscription at any time.
How much filling do you use?
For one cat, expect to use about 2 bags per month. Good to know: an automatic litter box uses litter more efficiently than a regular one. Because the sieve removes only the clumps after each use, the rest stays clean, and you don’t have to empty the entire box every week.
Frequently asked questions
Can I use regular filling from the supermarket?
Yes, as long as it forms clumps, it works in an automatic feeder. The quality varies significantly by brand, though: you’ll immediately notice weak clumps and a lot of dust in the results.
How much filling should go in the pan?
Fill it up to the fill line on your container. Too little filling results in weak clumps that stick to the bottom. Too much is a waste: the sifter can’t handle the excess, so clean grit ends up in the trash bag or spills over the edge.
How often should I completely replace the filling?
Much less often than with a regular litter box, because the soiled litter is removed after each use. Be sure to refill it regularly, and completely replace the litter when you clean the box.
What is the best litter for an automatic litter box?
A high-quality, fast-clumping litter: bentonite if you’re looking for maximum clumping power, plant-based if you want something light and natural. Silica and wood pellets are out of the question.
Still trying to figure out which litter box to choose? Then read our complete guide to automatic litter boxes or check out our unbiased top 5 picks for 2026.
