Your kitten is growing. A little more every week. At some point you notice the rapid growth slowing down, the weight stabilising, the energy levels settling. And somewhere in that phase the question pops up: when do I actually stop feeding kitten food?

The answer isn’t simply “when the bag runs out.” Kitten food and adult cat food are fundamentally different in their nutritional make-up. Switching too early can cause growth deficiencies; switching too late leads to weight gain. And the switch itself needs to be gradual — going cold turkey causes digestive problems in most cases.

When is a cat ready for adult food?

The rule of thumb: most cats are fully grown around 12 months of age. But that doesn’t apply to every breed.

A Maine Coon isn’t fully grown until around 3 to 4 years old, but its kitten nutritional needs apply until about 18 months. After that, adult food is appropriate even if it’s still growing a little. If you’re unsure which category your cat falls into, ask your vet. A quick weigh-in and growth check will give you a clear answer.

Signs your kitten is ready to switch

Age is a useful guide, but behaviour and physical signs tell the full story. Your cat is ready when several of the following apply:

• ✓Your cat is 12 months or older (or 18 months for a large breed)
• ✓Growth has visibly slowed — they’re no longer gaining size week by week
• ✓Their weight has been stable for several weeks with no sudden jumps
• ✓They’re eating consistent portions without excessive hunger or wolfing food down
• ✓Your vet described growth as complete at the last check-up

Only one or two boxes ticked? Wait another month and reassess. Rushing this transition is the enemy of a smooth switch.

Why you should transition gradually

A cat given a completely different food overnight will react physically. Not because the food is bad, but because the digestive system needs time to adapt to a different balance of proteins, fats and fibre.

With an abrupt switch you’ll often see: loose or soft stools, vomiting in sensitive cats, reduced appetite or outright refusal of the new food. In rare cases also lethargy or stomach pain. A gradual transition over two to four weeks eliminates these problems almost entirely.

The transition week by week

Mix the food together in the bowl so your cat can’t pick around the new food. Some cats are clever enough to sort it out. In that case, mix more finely or choose a brand combination where the kibble looks more similar.

• Week 175% kitten food, 25% adult food. Monitor stools and appetite. No issues? Move to week 2.
• Week 250% kitten food, 50% adult food. Your cat starts getting used to the new taste and texture.
• Week 325% kitten food, 75% adult food. The transition is nearly complete.
• Week 4Fully adult food. Also update the feeding schedule to 2–3 meals per day.

Got a sensitive cat? Stretch the transition to 6 to 8 weeks by holding each step for two weeks. More time is never a problem; too little time often is.

What to update in the feeder app

The switch from kitten to adult food comes with a change in feeding schedule. A kitten aged 6 to 12 months eats 3 meals a day. An adult cat eats 2 to 3 meals a day, with larger portions each time.

In the Prime AnimalZ app you can update this in a few steps:

• ✓Reduce the number of meals in the feeder schedule from 3 to 2 per day
• ✓Adjust the portion size per meal based on your cat’s adult weight
• ✓Check via the HD camera after the first few days whether your cat is accepting the new schedule
• ✓Got multiple cats? Make sure the right cat is eating at the right feeder

Want a full step-by-step setup guide? Read our article on setting up the feeder via the app. Have both a kitten and an adult cat at home? Also read our article on feeding a kitten and adult cat together.

The right feeder for the transition period

During the transition, being able to set exact portions and times per cat makes life much easier. These are the most popular models chosen by customers managing the switch.

Special cases

Spayed or neutered cats

After spaying or neutering, a cat’s calorie needs drop by 20 to 30 percent. Regular adult food then provides too many calories, leading to weight gain. In this case, choose a food specifically formulated for neutered cats with lower energy needs. This also applies if your cat is already on adult food and suddenly gains weight after the procedure.

Kittens growing too fast or too slowly

Is your kitten growing faster than average? The switch can sometimes happen before 12 months. Growing slower than expected? Stay on kitten food for longer. In both cases, have your vet assess weight and growth objectively before making any changes.

Unwell kittens

If your kitten is unwell or has a sensitive stomach, now is not the time to switch. Wait until they’re fully recovered. Always check with your vet about the right timing if there’s a chronic condition or ongoing medication involved.

Time to upgrade the litter box too?

As your kitten grows into an adult cat, it’s also worth checking the litter box situation. Adult cats need more space than kittens. Browse our automatic litter boxes, suitable for large breeds and multi-cat households.

Signs the transition isn’t going well

Keep a close eye on your cat during the transition. Most cats sail through without any issues, but some react more strongly. Stop the plan and speak to your vet if you notice:

• ⚠Repeated vomiting after every meal: slow down the plan and temporarily reduce the proportion of new food.
• ⚠Complete refusal of the new food: try a different flavour or brand, or warm the food slightly to make the smell more appealing.
• ⚠Weight loss of more than 5% in two weeks: see your vet.
• ⚠Blood in the stools: stop immediately and go to the vet.
• ⚠Lethargy and reduced appetite for more than three days: vet required — this goes beyond a normal transition reaction.

Frequently asked questions

Want to learn more about feeding your cat? Read how much a kitten should eat per day or browse all automatic feeders.