When Do Cats Stop Growing

Cats start out life as tiny, helpless, blind, deaf bundles of fur called kittens. Yet fast forward just a handful of months and that tiny kitten will look very different – and weigh a lot more!

As your kitten grows up and gets bigger and stronger, its behavior and needs will change accordingly.

This is why it is so important to learn when do cats stop growing and how to prepare for each major milestone of your kitten’s growth.

When Do Cats Stop Growing

PetMD explains that cats generally stop growing at around the 12-month mark.

However, some cat breeds may reach adulthood earlier and other breeds may take up to two years to reach their full adult size.

Learn About the Development Stages from Kitten to Adult Cat

It may be hard to believe it, but your tiny kitten will go through six stages of growth before becoming an adult cat!

This short YouTube video will introduce you to the six major stages of cat growth.

An Overview of the Main Stages of Cat Growth

According to PAWS charity, these are the six main stages of cat growth from kittenhood to adulthood.

These are not to be confused with the major life stages a cat goes through. In this section, we are just addressing the stages a kitten must pass through to become an adult cat.

Neonatal growth stage

The neonatal growth stage starts the moment queening, or kitten birth ends. The newborn kitten instantly enters the neonatal growth stage and stays there for the first two weeks of life.

As Alley Cat Allies charity explains, there are many major milestones during this period of growth.

These are the major milestones that occur in the first two action-packed weeks of a kitten’s life:

  • Eyes open and eyesight starts to develop.
  • Ears begin to unfurl and open.
  • The senses begin to wake up – smell, taste, touch.
  • The kitten learns how to move and walk around.
  • Weight doubles in the first two weeks.

It is important to handle the kittens gently but consistently so they get used to human contact.

Socialization growth stage

Starting at the beginning of the third week of a kitten’s life, they have enough sensory awareness and physical strength to begin socializing with littermates and their mom.

They will begin to explore their near vicinity and venture a little bit farther away from the mother cat. Kittens will also start to groom themselves and each other and push their bodies more, learning to pounce, jump and even run.

This early socialization stage will last through the seventh week of a kitten’s life.

Play growth stage

The play growth stage overlaps a little with the socialization stage. It really begins in week seven.

This is when you will see the kittens playing more with each other, watching the mother cat for clues about how to behave and how to play.

Weaning is in full swing around this time as is litter box training, further encouraging the kitten to become more independent from the mother cat.

Ranking growth stage

Starting around the nine-week or three-month mark, kittens begin to find their place in the litter and also with their human carers.

You will start to see more facets of your kitten’s adult cat personality coming out. You will also see adult cat behaviors replacing kitten immaturity. Meals and sleep patterns will regulate and your kitten will be fully weaned.

On a related note, your kitten will also be losing their baby teeth and getting their full set of adult teeth.

Starting around the fourth month of life, kittens will begin to achieve sexual maturation and you can clearly distinguish the boy kittens from the girl kittens.

The ASPCA states that kittens are often neutered or spayed during this growth stage – sometimes as early as eight weeks old. While this is generally considered to be safe, always talk with your feline veterinarian for exact guidance.

Adolescence growth stage

Starting around the six-month mark in the adolescence growth stage, your kitten will truly begin to look and act like a young adult cat.

If you have not had your kitten neutered or spayed, now is definitely the time to start planning for this procedure. Otherwise, you can expect your male kitten to begin spraying urine to mark areas in the house and yard.

Your female kitten will enter her first heat and there is the chance she could become pregnant if you do not keep her indoors and away from male intact cats in the neighborhood.

Your kitten will be keen to explore, play and test the limits of your patience. It is also the time to start the transition away from kitten food and towards adult cat food, according to My Cat Care Clinic.

Early adult growth stage

Depending on your cat’s specific breed, the early adult growth stage might begin as early as 11 months or as late as 18 to 24 months of age.

When your specific cat reaches true adulthood will depend on genetics, gender, diet, enrichment, socialization, and, most importantly, breed.

Larger cat breeds may take up to two years to reach their full adult size and weight, while dwarf, miniature, or teacup felines may be fully grown before the age of one year old.

Five Kitten to Cat Life Stages

According to the American Association of Feline Practitioners, there are five main life stages that a feline goes through.


As we have highlighted in the earlier sections of this article, kittenhood is generally acknowledged to be the period of time from birth through 12 months old.

But for some cat breeds, kittenhood can technically extend all the way to 24 months old.

Young adulthood

Young adulthood for felines is typically considered to start at one year old and extend through the sixth year of life.

This is the life stage that is often called the “prime” of a cat’s life.

Mature adulthood

Starting around year seven, a cat enters the mature adulthood phase of life.

Depending on your cat’s breed and lifespan expectancy, this phase can overlap with the start of the senior phase of life.

Senior adulthood

The senior adulthood phase of a cat’s life starts around age 10 but can start earlier in some breeds and later in others.

End of life

The end of life stage does not have a specific chronological start time. It begins when the quality of life begins to noticeably decline. During this life stage, it is important to monitor your cat’s wellbeing and life quality and make comfort a priority.

How to Know For Sure Your Cat Is Fully Grown

Since there are several variables that can influence when a specific cat is done growing, one of the most consistent measurements veterinarians use is weight.

The reason is simple: weight stabilization has been shown to coincide with behavioral stabilization.

As Healthy Paws Pet Insurance & Foundation points out, one of the easiest ways to measure this is to make a note of your kitten’s weight at 16 weeks old.

When your cat’s weight has doubled that number, there is a high likelihood your cat is done growing and is now an adult.

Your veterinarian will be the best resource to verify your cat is grown