Two boxes side by side read as one box to a cat
Eliminating outside the box is far more often an environment signal than a habit. This calculator takes the cats living together, the floors they can reach, the boxes you have now and the separate spots those boxes stand in, then reports the advised count and the shortfall. Because it counts spots rather than boxes, a home with two boxes pushed together sees that reflected in the result.
The advised count follows AAHA and AAFP feline life stage guidance: one cat is advised two boxes in two separate spots, a multi-cat home gets the number of cats plus one, and a home with several floors needs at least one box per floor. The same guidance notes that boxes side by side read as a single box to a cat, and that boxes belong away from the food and water bowls. Current as of October 2026.
Litter type, box size and hoods are outside this page. If elimination outside the box continues after the count is met, do not keep working on the environment alone: urinary disease has to be ruled out first. Straining with almost no urine passing can turn life-threatening within hours and is not something to wait on. This tool is for reference only and does not replace veterinary care. Contact your veterinarian right away if you notice symptoms or suspect a problem.
Frequently asked questions
Because somewhere else has to be available when one box is soiled or feels unsafe. AAHA and AAFP guidance advises two boxes in two separate spots even for one cat.
A cat reads boxes side by side as one box. That is why this calculator credits only as many boxes as there are separate spots.
When the eating place and the toilet place overlap, cats start avoiding the box. Put it somewhere quiet with an escape route instead.