Free Litter Box Calculator
A litter box calculator helps you plan how many trays your cats need and how much litter to buy. Start with one box per cat plus one extra, and at least one on each floor your cats use.
Your household
Litter shopping assumptions
Defaults are examples for an open rectangular tray, not a recommended box size or change schedule. Measure your tray and follow your litter's instructions. Every box is assumed to be the same size.
Your litter box plan
3 boxes
Use the greater of cats + 1 (3) or floors (1). This is a starting point; cats that avoid each other may need additional separate locations.
- Initial fill, all boxes
- 23.6 L
- Ongoing use per 30 days
- 63.5 L
Each fill uses about 7.9 L per box. Ongoing use = initial fill × 30 ÷ days between changes + top-ups per box × boxes × 30 ÷ 7. The initial setup fill is separate from ongoing use. This is an average shopping estimate, not a prediction of waste or exact purchase dates.
Liters measure volume. Do not treat these figures as kilograms or pounds; litter density varies by product. Scooping frequency does not change this volume estimate.
Placement and care
- Put at least one box on each floor your cats use. Spread boxes into separate quiet, accessible locations; a row of trays in one room gives cats fewer independent options.
- Keep boxes away from food, water, loud appliances, and places where another pet could block the exit.
- Keep scooping at least daily, even with spare boxes. More frequent cleaning does not remove the need for separate locations.
- Choose a box with room to turn around comfortably. If toileting habits suddenly change or your cat seems uncomfortable, contact your veterinarian.
How to use the calculator
- Enter your number of cats and the floors they use.
- Select life stage, mobility needs, and scooping frequency.
- Adjust tray dimensions, litter depth, replacement days, and weekly top-ups to match your routine.
- Review the box count, litter estimate, and placement notes, then print the plan for your household or sitter.
Litter box FAQ
How many litter boxes do I need for two cats?
Start with three boxes: one per cat plus one extra. Place them in separate accessible locations. In a home with more than three floors used by the cats, provide at least one box per floor.
Can two cats share one litter box?
Some cats will share, but a single box gives them no alternative if it is dirty, occupied, or blocked. The general starting guideline is one box per cat plus one extra.
Does an extra litter box mean I can clean less often?
No. Scoop waste at least daily. Extra boxes and deeper litter do not replace regular cleaning. Follow the litter manufacturer's instructions for complete litter changes and wash the tray regularly.
How much cat litter will I use each month?
It depends on box size, fill depth, litter type, replacement schedule, and top-ups. This calculator estimates an ongoing 30-day volume from your own assumptions. Liters cannot be converted directly to bag weight without knowing the product's density.
Where should litter boxes go for a senior cat?
Choose quiet, easy-to-reach places near the cat's usual areas, with a low-entry tray if needed. Keep a box on each used floor so stairs are not the only way to reach one. Keep trays away from food and water.
Sources and calculation notes
The Humane Society's litter box guidance supports one box per cat plus an extra, a box on each floor, low accessible entries, quiet placement, and daily scooping. Checked November 3, 2026. The calculator combines the two count guidelines with max(cats + 1, floors); it does not add them together.
Volume uses inside length × width × litter depth ÷ 1,000 to convert cubic centimeters to liters. Box shape, rounded corners, litter density, waste removal, and your cats' habits affect real use. Adjust the example assumptions to your product and routine; no data is saved or sent by this calculator.