Have you found yourself with a new kitten to take care of? In this post, you'll learn that their needs will evolve as they grow, so you'll have to be able to tell how old they are. Our Union City vets discuss how to do this.

Why It's Important to Identify a Kitten's Age

If you've brought a new kitten home, knowing just how old it might be is vital to taking proper care of it. Since kittens' needs change so quickly, the requirements of a one-week-old kitten will be dramatically different than those of a four-week-old kitten. 

How to Tell a Kitten's Age 

While we will cover more detail later in this post, here are four simple steps you can follow to obtain reasonably accurate insight into your kitten's age. 

1. Look at Their Teeth 

Here's how to tell how old a kitten is by its teeth.

A kitten's baby teeth will emerge around three weeks old, followed by permanent teeth around three or four months old. The middle incisors are typically the first to appear around 14 weeks, followed by the second and third incisors at 15 and 16 weeks, respectively. 

Kitten teeth are extremely small, making it difficult to distinguish between baby and permanent incisors. It is easiest to check their mouth on a regular basis during this time period, when you may be able to see some of their baby teeth and some permanent teeth and compare their sizes. Baby teeth are smaller with pointed tips, whereas permanent teeth are slightly wider with flat edges.

2. Check Your Kitten's Weight 

A kitten's weight in pounds is roughly proportional to his age in months, and he will gain weight at a relatively predictable rate until he is about five months old. As long as a kitten is physically healthy, a one-pound kitten is about a month old, and a three-pound kitten is about three months old.

3. Confirm Whether They Have Opened Their Eyes 

Kittens are born with their eyes closed, and will open them once they reach about 10 days old. 

4. Watch for Signs of Walking or Playing 

Most kittens begin walking around three weeks of age, but it takes a little longer for their movements to become completely coordinated. A kitten that is walking well and playing is probably at least one month old.

Kitten Age Chart: Development & Behavioral Milestones 

To achieve the most accurate age estimate for your new kitten, you'll likely need to bring them to a vet for their first veterinary checkup. Here are some milestones you can watch for to estimate your kitten's age more accurately. Use this information like a "kitten age chart": 


  • Their eyes are still closed, and their ears are folded. 
  • The umbilical cord is still attached. 
  • The nose and paws may be pink in color. 
  • They are still unable to see or hear. 
  • They typically weigh between 80 – 110 grams. 
  • Body temperature is usually low, around 95 – 97 degrees. 

One Week Old 

  • Their eyes still remain closed. 
  • The umbilical cord is no longer attached.
  • At round the seven-day mark, their ear canals will begin to open. 
  • When they are around 8 – 12 days old, their eyes will gradually begin to open. Never try to pry open a kitten's eyes; allow this process to unfold on its own. 
  • By the time they are one week old, your kitten should have doubled his birth weight (to about 150 – 250 grams). 

Two Weeks Old 

  • By this time, your kitten's eyes will be fully open and baby blue in color. His vision will still be developing. 
  • The ear canals will be open and the ears will appear small and rounded, similar to a baby bear cub. 
  • While your kitten will be wobbly on their feet, they will start trying to develop their coordination and movement. 

Three Weeks Old

  • Their first teeth will begin to erupt. The tiny teeth at the front of the mouth called the incisors, will start to poke through the gums.
  • Ears that point upwards.
  • At this age, kittens will be walking, exploring their surroundings, and even beginning to explore their litter box.

Four Weeks Old

  • Your kitten's teeth will continue to develop and by this time their canine teeth will start to poke through the gums.
  • Four-week-old kittens will be confidently exploring and developing more coordination that allows them to walk, run, and even begin to play.
  • Your kitten should still weigh roughly 1 pound.

Five Weeks Old

  • The premolars will start to emerge, indicating that a kitten is ready to be introduced to weaning onto wet food.

Six Weeks Old

  • The kitten's deciduous teeth will have fully emerged, and she will typically be perfecting her weaning onto wet food.

Seven Weeks Old

  • The kitten will have all of their baby teeth. Most seven-week-old kittens will be fully weaned onto wet food.
  • At this age, the adult eye color will begin to emerge. Kittens' eyes will change from baby blue to the eye color they will keep permanently. Kittens with grey, green, or yellow eyes are likely 7 weeks or older.

Eight Weeks Old

  • Most kittens will be eating independently.
  • Kittens of this age will have their permanent adult eye color.
  • Your kitten should weigh roughly 2 pounds.

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.

Are you caring for a new baby kitten? Contact our Union City vets today to book an exam so we can help you set them up for a long, healthy life.