Four Litter Types: Dust, Clump Strength, Tracking

Litter choice is a trade of four measurable things, not a matter of taste: dust raised when pouring, clump strength under load, grams carried out on the paws, and cost per liter of working litter. No type wins all four. Bentonite wins on clump strength at 300 to 600 g and loses on dust at 8 to 15 mg per cubic meter. Tofu wins on dust at 2 to 5 mg and loses on clump strength at 150 to 300 g. Pellets and silica sit in between and ask for a different box.

Measure your own baseline before switching: pour 2 L of litter from 30 cm into a tray in still air and watch how much dust hangs for 30 seconds. That single test predicts most of what follows.

Dust: the number that decides the room

Dust is measured as suspended particulate during a pour, and the spread between types is roughly 5 to 15 times. Bentonite clay, especially the fine 0.5 to 2 mm grade, runs 8 to 15 mg per cubic meter at the pour point and settles over 10 to 20 minutes. Tofu and pea-fiber litter runs 2 to 5 mg. Pine pellets run 4 to 9 mg but shed sawdust steadily as they break down, so daily dust can exceed the pour number after 5 to 7 days. Silica crystal runs 1 to 3 mg, the lowest of the four.

For a cat with a history of airway signs, or a household with an asthmatic person, the practical threshold is under 5 mg per cubic meter at the pour plus a hooded box. Anything above 10 mg means pouring outdoors or into a low-sided tray, and a 30 second wait before the cat goes back in.

Clump strength: grams of load before it breaks

The working test is simple: wet 50 mL of litter, wait 60 seconds, lift the clump by one edge. Bentonite holds 300 to 600 g without breaking and survives a 20 cm drop. Tofu holds 150 to 300 g, breaks at the scoop edge when the box is shallow, and leaves 2 to 5 mm crumbs behind. Pellets do not clump at all: they absorb and collapse into sawdust, which is why they need a sieve tray or a two-layer box. Silica absorbs 30 to 40 percent of its own weight and holds urine in the bead, so there is no clump to scoop, only solid waste.

Clump strength drives litter use more than unit cost does. A clump that breaks means crumbs stay in the box, odor rises at 5 to 7 days, and the whole tray gets dumped at 10 to 14 days instead of 21.

Tracked grams per exit

Tracking follows particle size and weight. Bentonite at 0.5 to 2 mm carries 3 to 8 g per exit. Tofu at 2 to 3 mm carries 5 to 12 g because the pieces are light and ride high in the paw. Pellets at 4 to 8 mm carry 2 to 6 g, the least of the four. Silica at 2 to 5 mm carries 4 to 10 g and rolls. A mat with 8 to 12 mm cells removes 50 to 65 percent of these loads; the rest lands 1 to 2 m out.

Cost per liter, indexed

Cost per liter is the only fair price comparison, because bag weight says nothing about useful volume. Divide the bag price by the liters it fills, then divide again by the days it lasts. Indexed against the cheapest type at 1.0, bentonite lands at 1.0, pine pellets at 0.7 to 1.0, tofu at 1.6 to 2.2, and silica at 2.0 to 2.8. Tofu and silica last longer per liter, which narrows but does not close the gap: expect 1.2 to 1.6 times the monthly cost of bentonite.

All four types in one table

Type	Grain mm	Dust mg/m3	Clump strength g	Tracked g/exit	Cost index	Full change d
Bentonite clumping	0.5-2	8-15	300-600	3-8	1.0	14-21
Tofu or pea fiber	2-3	2-5	150-300	5-12	1.6-2.2	14-21
Pine pellet	4-8	4-9	none	2-6	0.7-1.0	5-7
Silica crystal	2-5	1-3	none, absorbs 30-40%	4-10	2.0-2.8	21-30

Conditions where each type fits

Box size scales with body length, so a 45 cm cat needs a box of 60 cm and up, and a Maine Coon or Ragdoll needs 70 cm or more; per-breed averages sit in the breed quiz. Grain size then has to match the box: pellets need a sieve tray, clay needs 5 to 7 cm of depth in a box with 20 cm sides.

Bentonite fits a healthy adult cat, a box of at least 60 cm, litter depth 5 to 7 cm, and a room with a window or a hooded box. It needs full changes every 14 to 21 days and 2 scoops a day. It does not fit a cat that sneezes at the box or a kitten under 8 weeks that tastes litter.

Tofu fits a household where dust matters, a cat that likes a soft surface, and an apartment with no outdoor bin, since small amounts can go to the toilet one clump at a time. It needs a deeper bed, 6 to 8 cm, because light pieces scatter, and full changes every 14 to 21 days.

Pine pellets fit a two-layer box with a sieve, a cat that does not mind a coarse surface, and a household that wants the lowest tracked grams. The sawdust has to be emptied every 2 to 3 days or the box smells at day 5. Full change every 5 to 7 days.

Silica fits a single cat, a small apartment, and low-scooping routines: 1 scoop a day, full change every 21 to 30 days. Beads crush under a 5 kg cat and the dust rises after 14 days, so stir the bed at day 10 and replace on schedule.

Transition and the 14-day check

Switch over 7 to 10 days, mixing 3 parts old to 1 part new for 3 days, then half and half for 3 days, then the new litter alone. Watch for 2 signals: exits from the box under 20 seconds and no urine outside for 3 days. If either fails, step back one stage for 3 days rather than pushing through. Keep every water source at least 1 m from the box, and if the cat also drinks little, treat that as its own problem: water play and moving water change intake in a way no litter swap will.

Pour 2 L from 30 cm and time the dust cloud; above 10 mg per cubic meter, switch or pour outdoors.
Test clump strength by lifting a 60 second old clump; under 150 g, add depth to 6 to 8 cm.
Keep litter 5 to 7 cm for clay and 6 to 8 cm for tofu, and scoop 2 times a day.
Weigh what the mat catches for 3 days; over 5 g a day, add a mat or change grain size.
Do not put a cat with urinary signs through a litter change: straining for 12 hours needs a vet, not a new bag.

Terms mentioned in this article

Frequently asked

Which litter type has the least dust?

Silica crystal, at roughly 1 to 3 mg per cubic meter at the pour point, followed by tofu at 2 to 5 mg. Bentonite is the highest at 8 to 15 mg. Dust matters most at the pour, so pour outdoors or into a low tray, wait 30 seconds, and keep the box hooded if anyone in the home has airway problems.

Why do my clumps break when I scoop?

Usually depth and time. Clumps need 60 seconds and 5 to 7 cm of litter to reach 300 to 600 g of strength in bentonite, and 6 to 8 cm for tofu, which tops out at 150 to 300 g. Scooping within 30 seconds, or a bed under 4 cm, breaks clumps and leaves crumbs that shorten the full change to 10 to 14 days.

Is cost per liter really different from bag price?

Yes, by 1.6 to 2.8 times. Bag weight says nothing about useful volume, so divide bag price by the liters it fills and again by days it lasts. Indexed at 1.0 for bentonite, pine pellets run 0.7 to 1.0, tofu 1.6 to 2.2, and silica 2.0 to 2.8, though the two expensive types also last longer per liter.