Four types of cat litter side by side
Independent material comparison
Most people buy the litter they have always bought. Yet the material determines how often you need to clean, how much dust drifts through your home, what it costs you per month — and whether you can see anything about your cat's health. Below we compare silica gel, clumping clay, wood pellets and tofu on eight points.
Short answer: silica gel wins on absorption, odour control and cleaning rhythm, and it is the only material on which a health indicator works.
Per bag it costs more than clumping clay. Per month it usually doesn't — we do the maths further down.
Material 1 of 4
Silica gel
Silica gel consists of porous crystals that absorb moisture rather than holding it on the outside. This keeps the box dry, makes one bag last longer than a bag of clumping clay and keeps odour under control for weeks rather than days. The material is virtually dust-free, which helps cats and people with respiratory complaints.
Because the crystals are light in colour and urine is absorbed into the crystal, silica gel is the only one of these four materials on which a colour indicator works reliably.
Where it falls short: silica gel doesn't clump. Anyone used to scooping a clump once a day has to get used to a different rhythm. The price per bag is higher, and the crystals are harder underfoot than some cats like.
Material 2 of 4
Clumping clay (bentonite)
By far the best-selling material in the Netherlands, and not without reason. Bentonite forms a solid clump around urine that you scoop out in one go. That makes daily maintenance simple and predictable, most cats accept it without any adjustment, and per bag it is the cheapest of these four.
Where it falls short: bentonite is heavy, noticeably dusty, and any moisture not caught in the clump stays in the box. As a result, odour builds up after a few days and the whole box needs emptying more often. Urine disappears into a grey clump — you can't tell anything from it.
Material 3 of 4
Wood pellets
Compressed wood fibre, usually a by-product of the timber industry. The material is light, cheap and scores best of these four on waste disposal — depending on your municipality, it can go in the organic waste. The wood scent masks urine well at first.
Where it falls short: the pellets break down into sawdust on contact with moisture. That means scooping through an ever finer layer, and sawdust carried out of the box. The box needs emptying completely more often than with silica gel, and the colour of wet sawdust tells you nothing about health.
Material 4 of 4
Tofu (plant-based)
Made from a soy by-product. It combines two properties that rarely go together: it clumps and it is flushable and compostable. The pellets are soft underfoot and produce little dust, making it a logical choice for kittens and for cats that have just had surgery.
Where it falls short: tofu is the most expensive per bag of these four, the range in the Netherlands is small and quality varies widely by brand. In warm weather the material can start to smell. And here too: the clump tells you nothing about the cat that made it.
The four materials side by side
Calculated for one cat, one box, standard pack or standard subscription, shipping included.
Values apply to the material category, not to one specific brand. Where a figure varies too much per brand to support across the category, we leave it blank.
The costs
More per bag, not per month
This is the point where most people drop off, and rightly so: side by side on the shelf, silica gel is clearly the more expensive bag. But you're not buying bags, you're buying months.
A bag of clumping clay lasts less long for one cat than a bag of silica gel, because moisture not caught in the clump stays in the box and the whole box needs emptying more often. Convert the price per bag to the price per cat per month and the difference becomes small — with some brands it disappears.
What remains is a difference in when you pay, not how much. And with a subscription you pay for that bag per month anyway.
Silica gel makes a health indicator possible. Not every silica litter has one.
That's why the table above says "possible" and not "present". You now know which material you want. What remains: which bag. In the rows below, the difference no longer lies in the material, but in what the manufacturer adds to it — and whether you can read that colour yourself.
Within silica gel: which bag
Same calculation: one cat, one box, standard subscription, shipping included.
We're level on the first row. The difference lies in rows 2 and 3.
Why CatCheck
Three things we do differently from the rest of the shelf.
Blood detection
Blood in the urine is often the first sign of bladder problems, and you won't see it on grey clumping clay. CatCheck's crystals visibly change colour, even with traces you would miss with the naked eye in the box.
Colour guide in the bag
An indicator without an explanation is a colour you can't do anything with. Every bag contains a guide that tells you per colour what you're seeing, whether it's urgent and when to call the vet.
Cancel monthly
One bag is four weeks. The subscription runs monthly, you set the rhythm yourself and you cancel whenever you want — no notice period, no minimum order.
Switching from clumping clay to silica gel
Where these figures come from
This is CatCheck's own comparison. We sell silica gel, so feel free to check our work. The material values apply per category and are based on [bron nog invullen]. Where a value varies too much per brand to support across the category, we leave the cell blank rather than entering a number that only applies to one bag.
Prices are converted to one cat, one box, standard pack or standard subscription, shipping included. Data on other brands comes from their own product page on the date below. Last checked: [datum nog invullen]. We update this page every quarter.
Frequently Asked Questions
Won't the colour just change from anything?
No. The crystals react to the pH level of urine and the presence of blood, not to moisture as such. Water, food or cleaning products don't produce an indicator colour. Do look at the pattern over a few days, though, not at a single crystal.
Isn't silica gel simply expensive?
Per bag, yes. Per month usually not, because a bag of silica gel lasts longer for one cat than a bag of clumping clay and the whole box needs emptying less often. Convert it to the price per cat per month and the difference becomes small.
Will my cat accept it?
Most cats do, provided you do it gradually. Cats mainly react to the texture under their paws. In the first week, mix about a quarter into your current litter and build up over two to three weeks. Switching all at once is the main reason a changeover goes wrong.
Silica gel doesn't clump — so how do I scoop?
You only scoop out the solid waste and rake through the crystals once so the moisture spreads evenly. That is less daily work than scooping clumps; the difference is that the whole box is replaced at the end of the cycle.
Is it safe for kittens and older cats?
Yes, the material is suitable for cats of all ages. As with any litter, kittens that still nibble at everything are best kept under supervision for the first few weeks.
I have several cats — does the indicator still work?
You'll see that something is up, but not with which cat. If you want to trace it, temporarily use separate boxes. The rule of thumb is still one box per cat plus one extra.
What about dust and waste disposal?
Silica gel produces hardly any dust, which helps with respiratory complaints. On waste disposal it's fairer to say that wood pellets and tofu do better: they are compostable, while silica gel goes in the general waste.
Am I tied to a subscription?
No. The subscription runs monthly, you set the frequency yourself and you cancel whenever you want. No notice period, no minimum order.