Most cats can figure out how to use a litter box in 3 to 7 days if it is in the right location, has the appropriate litter, and is kept clean. Kittens typically learn from their mothers by the time they are 4 weeks old. For adult or rescue cats, opt for an open, low-sided box, position it in a quiet and accessible area, and gently lead your cat to it after they eat and sleep.