What to Expect: Kitten Growth and Development

What to expect: Kitten growth and development

A basketful of kittens is a sight that’s sure to melt the frostiest of hearts. Those furry felines are cute, they’re curious and they seem oh-so-helpless. But before you become one of the millions of people in the U.S. who take home a cat (or cats) every year—2.1 million of whom adopt from shelters, according to the American Society for the Prevention of Cruelty to Animals (ASPCA)—here’s some vital information about what milestones to expect and when.1 These weekly and monthly kitten development milestones will help you be the best possible pet parent to your quickly growing little cat.

Newborn to 4 weeks old kitten

As spring days get warmer and longer, cats enter their breeding season. A female cat can become reproductively mature enough at the young age of 6 months.9 Known now as a Queen, she’ll give birth to a litter of between 3 and 5 kittens that are wholly dependent on her care: She will clean them, nurse them, keep them warm and even stimulate urination and defecation for them. Kittens are born with a good sense of smell, which is crucial for them to help locate their food source—milk!


  • Opening eyes and ears: Kittens are born with their eyes and ears sealed shut, rendering them blind and mostly deaf. The ear canals typically open between 10 days and 2 weeks of age, and the eyes open between 1 and 2 weeks.10
  • First teeth: Kittens are born with no teeth and will start to get deciduous (“milk”) teeth around 3 weeks of age.
  • First steps: Most kittens can stand by 10 days of age and can walk on their own by 3 weeks.10

4 to 10 weeks old kitten

Wondering when to start socializing your kitten? It’s now! Socialization is an essential kitten milestone that you don’t want to neglect. You want her to know, love and trust you—so begin by spending at least an hour per day handling, petting and holding her to ensure she’s comfortable living with humans when she becomes an adult. You’ll start to see her putting on a pound a month once she’s been weaned and starts to eat solid kitten food.


  • Using a litter box: Kittens are usually fully weaned by 8 to 12 weeks old.2 They can now be trained to use the litter box.
  • On the move: By 6 to 8 weeks, kittens are agile and active!
  • Weight gain: Kittens usually weigh 3 to 4 ounces at birth, and by 1 month of age, they weigh a pound. A general rule is that kittens gain about a pound a month until 6 months of age.
  • Personality: Your 6-week-old kitten’s behavior will start to show you who she really is.3
  • Ready to play: Kittens are ready for some toys at 7 to 8 weeks old. Just make sure balls, stuffed mice and whatever else you choose are not small enough to be swallowed.4

3 to 6 months old kitten

At around 8 to 12 weeks old, most shelters and breeders will be ready to separate a kitten from his mother and let you bring him home. Your kitten’s development really starts to pick up now. Watch him become ever more active and playful, and here comes his full set of adult teeth! Kittens can reach sexual reproductive maturity very quickly and should be spayed or neutered between 4 and 6 months of age to prevent unwanted pregnancies and behaviors such as urine marking in male cats.


  • More teeth: Kittens have 26 deciduous teeth, which will fall out and be replaced by 30 permanent teeth by the time they are 6 months old.
  • All solids: Kittens are fully eating solids by now, having foregone supplemental mother’s milk right around the 3-month mark.
  • Socialization: Around 9 weeks until about 16 weeks of age, kittens enter a second socialization period where they learn how to play and interact with you and their fellow felines. They also start to strike out more on their own to explore their environment.
  • First vet visit: Between 6 and 8 weeks of age is when your kitten should visit the vet for the first time. She should be dewormed (if she hasn’t already been) and vaccinated. Kittens need vaccines to be performed in a series until they are 16 weeks of age in order to ensure they develop immunity to diseases.

7 months to 1-year-old kitten

Your now extremely confident kitten has begun to look more and more like a full-grown cat, with his body beginning to fill out and lengthen. He’s also ready to start getting into some serious trouble, so kitten-proofing is essential!

Get ready for all your hard work in socializing your kitten to start to pay off. According to The Spruce Pets, now’s the time he’ll start to snuggle with you voluntarily.

7-month-old milestones:

  • Extra-snoozy: Your kitten has been growing at a rapid pace by now and he’ll be spending half his day or more napping, just like an adult cat.
  • Socialized: Your kitten is ready to show you how much he loves you—when he isn’t napping or exploring, that is.

8-month-old milestones:

  • Pushing limits: A confident cat is a cat that likes to see how far she can take those shenanigans (pushing objects off the shelves, climbing the kitchen cabinets) before it’s too far. The trick for you: patience.

9-month-old milestones:

  • Chewing: With a full set of teeth, your kitten may begin to discover how fun it can be to chew and gnaw on things.

10-month-old milestones:

  • Eating like a grown-up: Now’s the time to start switching up your kitten’s nutrition by transitioning him to adult cat food. Make sure you go slow to keep him from getting an upset stomach.

1-year-old milestones:

  • Congratulations! Your baby is now fully grown and looking forward to a healthy and happy long life with you and your family.

Kitten growth chart:

Age Weight Milestone
Newborn About 3.5 ounces5 Eyes open at 9 to 14 days old6
2 months 2 lbs7 Fully weaned and using a litter box2
6 months 6 lbs7 Bold, socialized and eating solid food3
1 year 5-25 lbs8 Eating adult food, napping, playing, full-fledged member of the family3

How to tell my cat’s age?

If you’re not sure how old your cat is, you can use these four steps from the ASPCA to ballpark a kitten’s age:7

  • How do his teeth look? A cat gets its first baby teeth at 3 weeks, and permanent teeth come in around 3 to 4 months.7
  • How much does he weigh? A healthy kitten’s weight in pounds roughly corresponds to his age in months. So a 1-pound kitten is about 1 month old and a 3-pound kitten is about 3 months old.7
  • Are his eyes open? A kitten’s eyes open at 10 days of age.7
  • Is he walking and playing? A healthy kitten starts walking by 3 weeks and is generally coordinated by 1 month of age.7

From Pets Best

If you have questions about your kitten’s development, you should connect with your veterinarian. Another option is a pet helpline. Every Pets Best policy allows policy holders to speak directly to a veterinary professional with the 24/7 Pet Helpline included with their pet insurance policy. Get a quote today to begin protecting your pet!


1“Pet Statistics,” Author unknown (2022), American Society for the Prevention of Cruelty to Animals, https://www.aspca.org/helping-people-pets/shelter-intake-and-surrender/pet-statistics, Accessed on November 13, 2022.

2“Weaning a Kitten From Mother’s Milk to Solid Food,” WebMD Editorial Contributors (July 12, 2021), Fetch by WebMD, https://pets.webmd.com/cats/weaning-kitten, Accessed on December 12, 2022.

3“Kitten Development From 6 Months to 1 Year,” Adrienne Kruzer (February 2022), The Spruce Pets, https://www.thesprucepets.com/your-kittens-first-year-552271, Accessed on November 13, 2022

4“Kitten Exercise,” Author unknown (November 13, 2022), Purina Australia, https://www.purina.com.au/kittens/exercising/exercise#:~:text=A%20healthy%20kitten%20is%20a,predatory%20play%20with%20inanimate%20objects., Accessed on November 13, 2022.

5“Newborn Kitten Care,” WebMD Editorial Contributors (February 16, 2021), Fetch by WebMD, https://pets.webmd.com/cats/guide/newborn-kitten-care, Accessed on December 15, 2022.

6“Your Kitten’s Development in the First Six Weeks,” Franny Syufy (June 29, 2022), The Spruce Pets, https://www.thesprucepets.com/kittens-first-six-weeks-552276, Accessed on December 15, 2022.

7“Telling a Kitten’s Age in Four Steps,” Author unknown (2021), American Society for the Prevention of Cruelty to Animals, https://www.aspcapro.org/resource/telling-kittens-age-four-steps, Accessed on December 13, 2022.

8“The ideal cat weight: how heavy should my cat be?” Author unknown (no date), My Family Vets, https://www.myfamilyvets.co.uk/how-heavy-should-my-cat-be, Accessed on December 15, 2022.

9“Estrous Cycles in Cats,” Weir, M., Llera, R., & Yuill, C. (no date), VCA Animal Hospitals, https://vcahospitals.com/know-your-pet/estrus-cycles-in-cats, Accessed on December 20, 2022.

10“Kitten Milestones and Development Stages by Week,” Author unknown (no date), Purina, https://www.purina.com/articles/kitten/health/kitten-development-stages, Accessed on December 20, 2022.

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