Cat Litter Calculator
Weight of cat litter and number of 14 lb or 6.35 kg bags to fill your boxes once, from box size, depth and count; clay or any litter by its density. How it works
Use the Cat Litter Calculator
About the Cat Litter Calculator
An 18 × 14 inch litter box filled 3 inches deep holds 0.44 cubic feet, which is 17.5 lb of clay litter at the 40 lb per cubic foot this tool assumes. That is 1.3 bags of 14 lb, so buy 2. Two such boxes need 35.0 lb, or 2.5 bags, so buy 3. The figure is one complete fill, not a monthly supply.
One fill by box size
| Box (length × width × depth) | Cubic feet | Pounds | 14 lb bags | Bags to buy |
|---|---|---|---|---|
| 16 × 12 × 3 in | 0.33 | 13.3 | 1.0 | 1 |
| 18 × 14 × 3 in | 0.44 | 17.5 | 1.3 | 2 |
| 24 × 18 × 3 in | 0.75 | 30.0 | 2.1 | 3 |
| 22 × 16 × 4 in | 0.81 | 32.6 | 2.3 | 3 |
One box, imperial units, at 40 lb per cubic foot. Pounds and bags are rounded to one decimal as the tool shows them; the bags to buy are rounded up from the exact figure.
Depth in an 18 × 14 inch box
| Depth | Pounds | 14 lb bags | Bags to buy |
|---|---|---|---|
| 1 in | 5.8 | 0.4 | 1 |
| 2 in | 11.7 | 0.8 | 1 |
| 3 in | 17.5 | 1.3 | 2 |
| 4 in | 23.3 | 1.7 | 2 |
| 5 in | 29.2 | 2.1 | 3 |
| 6 in | 35.0 | 2.5 | 3 |
One box. The weight is proportional to depth.
Assumptions
- Clay litter at 40 lb per cubic foot (640.7 kg per cubic meter), the lowest density the cited patent gives for clay litter, unless you choose Other litter and type a density.
- A 14 lb (6.35 kg) bag unless you type your own bag size. The default is this tool's assumption.
- A straight-sided rectangular box, so the volume is length × width × depth.
How to use this tool
- Choose imperial (inches and pounds) or metric (centimeters and kilograms). Switching converts the numbers you already typed: 18 in becomes 45.72 cm.
- Enter the inside length and width of the box and the depth of litter you fill it to.
- Enter the number of boxes, 1 to 20. The results follow each edit: litter per box, total litter, bags, and the number of bags to buy.
Frequently asked questions
- How much cat litter do I need for a litter box?
- For an 18 × 14 inch box filled 3 inches deep, 17.5 lb of clay litter, which is 2 bags of 14 lb. The amount scales with the volume: the same box at 4 inches takes 23.3 lb and at 6 inches takes 35.0 lb.
- How many 14 lb bags of litter do I need for two litter boxes?
- Two 18 × 14 inch boxes filled 3 inches deep need 35.0 lb, which is 2.5 bags of 14 lb, so buy 3. The tool rounds the bag count up because you cannot buy half a bag.
- How much does cat litter weigh per cubic foot?
- This tool uses 40 lb per cubic foot (640.7 kg per cubic meter) for clay litter. That is the lowest figure in US patent 11,457,605, which says conventional clay-based litters typically have a density above 40 lb per cubic foot. Brands vary, so treat the result as a minimum for clay.
- Does this work for silica, pine or paper litter?
- Yes, if you know its density. Set Litter type to Other litter and type the bulk density from the bag or the maker's data sheet, 10 to 100 lb per cubic foot (160.2 to 1,601.8 kg per cubic meter). At 30 lb per cubic foot an 18 × 14 inch box filled 3 inches deep takes 13.1 lb, one 14 lb bag. The tool has no built-in figures for those litters because none was found from a maker or a test to cite.
- Is this how much litter I use in a month?
- No. It is one complete fill of the box at the depth you enter. How long that lasts depends on the number of cats and on how often you scoop and replace the litter, which the tool does not model.
- What bag size does the calculator assume?
- 14 lb (6.35 kg), the tool's own default rather than a figure from the source. Type your bag in Bag size (0.5 to 100 lb, or 0.25 to 45 kg): for two 18 × 14 × 3 inch boxes, a 35.0 lb total is 2 bags of 20 lb after rounding up 1.8. Add a Price per bag and the tool multiplies it by the bags to buy: 2 bags at $18 is $36.00.
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