Being used to feeding puppies for two years, I wasn’t sure how long Moe and Molly needed to be on kitten food.
After some research, it seems that felines should be on a kitten diet until they are 80-90% grown, which is generally about 6-9 months.
Some veterinarians recommend leaving kittens on kitten food until they are 12 months in order to ensure strong healthy bones and muscles.
It’s really up to you and your vet to decide when to stop feeding kitten food and switch to adult cat food.
When you do decide to make the switch, you want to ensure that you don’t upset your cat’s stomach by switching the food at once. You want to start with blending 3/4 kitten food and 1/4 adult food for a few days, and then 1/2 kitten and 1/2 adult food. After about a week lower the amount of kitten food to 1/4 percent kitten food and 3/4 adult cat food, and then make the full switch to 100% adult food.
If you have any kitten food left over, consider donating it to a shelter or friend who still has a younger kitten.