Is it normal for kittens to have looser stool than an adult cat?

A slightly softer, less formed stool than a mature adult cat’s is common in kittens, since their digestive systems are still developing and a diet change (a new food, a switch off mother’s milk or a household transition) can unsettle things temporarily. It should still be a defined shape rather than watery, and it should resolve within a couple of days rather than persist. True diarrhea in a kitten is a bigger concern than in an adult cat, since kittens dehydrate and lose weight much faster relative to their small size, so the same symptom carries more urgency at this age.

When to call a vet: Watery diarrhea in a kitten, or loose stool lasting more than two days, needs a same-day vet call rather than a wait-and-see approach, since kittens dehydrate quickly.