If you have recently adopted a kitten, it is important to be prepared for their changing needs. As kittens grow, their requirements also change, so you'll need to determine their age to provide the right care. Our veterinarians in Seattle have provided a comprehensive guide on how to determine the age of your kitten.


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

If you've rescued a new kitten, it is very important to figure out just how old it might be. This is because their needs change so fast. The needs of a one-week-old kitten will be dramatically different from the needs of a four-week-old kitten.

How to Tell a Kitten's Age 

Here are four simple steps to estimate your kitten's age.

1. Look at their teeth

Here's how to determine a kitten's age by its teeth. Baby teeth typically start to emerge at around three weeks of age, while permanent teeth begin to appear between three and four months old. The middle incisors usually emerge around 14 weeks, followed by the second and third incisors, which are permanent, appearing around 15 to 16 weeks after birth.

Kitten teeth are exceptionally small, making it challenging to distinguish between baby and permanent teeth. When inspecting a kitten's teeth for identification, take a look at these characteristics:

  • Size and Shape: Baby teeth are generally smaller and more pointed, whereas permanent teeth are larger and have flatter edges.
  • Color: Baby teeth are typically whiter, while permanent teeth may have a slightly yellowish tint.
  • Tooth Position: Baby teeth may appear more crowded in the mouth, whereas permanent teeth usually have more space between them as they grow.
  • Gumline: The gumline around baby teeth may appear more swollen or inflamed compared to that around permanent teeth.
  • Presence of Both: Sometimes, both baby and permanent teeth are present, allowing for a direct comparison based on differences in size, shape, and position.
By observing these characteristics, you can usually differentiate between a kitten's baby and permanent teeth. However, it's important to note that this method may not always be foolproof, especially in very young kittens where teeth are just beginning to emerge. In such cases, it's advisable to seek a professional assessment from a veterinarian.

2. Check your kitten's weight

A kitten’s weight roughly corresponds to their age in months, and they gain weight at a relatively predictable rate until about five months of age. As long as a kitten is in good condition, you can safely guess that a one-pound kitten is about a month old and a three-pound kitten is about three months old.

3. Whether they have opened their eyes 

Kittens are born with closed eyes and don’t open until about 10 days of age.

4.  Whether they are walking around or playing

Most kittens begin to walk when they are around three weeks old, but it takes a little more time, about an extra week, for them to gain coordination. You can safely assume a kitten walking well and playing is at least four weeks old.

Developmental & Behavioral Milestones

To accurately determine your new kitten's age, it's best to take them to the vet. However, you can look for certain milestones, such as those on the kitten age chart:


  • They have their eyes closed,
  • There's no umbilical cord.
  • Around 8-12 days, the eyes will slowly begin to open. Never try to pry open a kitten's eyes. Let them open on their own.
  • They should have doubled their birth weight (approximately 150-25- grams).

One Week Old

  • Their eyes are still closed
  • There's no umbilical cord.
  • At about 7 days old their ear canals will start to open.
  • Around 8-12 days, the eyes will slowly begin to open. Never try to pry open a kitten's eyes; let them open on their own.
  • The kitten should have doubled their birth weight (approximately 150-250 grams).

Two Weeks Old

  • The kitten's eyes will be fully open and baby blue in color, and their vision will still be developing.
  • The ear canals will be open, and the ears will be small and rounded, like a baby bear cub.
  • The kittens will be wobbly on their feet and attempting to develop coordination and movement.
  • They should weigh anywhere from 250-350 grams.

Three Weeks Old

  • A kitten's first teeth begin to erupt. The tiny teeth at the front of the mouth called the incisors start to poke through the gums.
  • The kittens will have ears that point upwards.
  • At this age, kittens will be walking, exploring their surroundings, and even beginning to explore their litter box.
  • The average kitten should weigh from 350-450 grams.

Four Weeks Old

  • Your kitten's teeth will continue to develop, and by this time, their teeth will start to poke through the gums.
  • They will confidently explore and develop more coordination, allowing them to walk, run, and even begin to play.
  • Your kitten should weigh roughly one pound.

Five Weeks Old

  • The premolars will start to emerge, indicating that a kitten is ready to be introduced to wet food.
  • Your kitten should now weigh roughly one pound.

Six Weeks Old

  • The kitten's deciduous teeth will have fully emerged, and they will typically be perfecting their weaning onto wet food.
  • At this stage, your kitten can weigh one pound to one and a half pounds.

Seven Weeks Old

  • The kittens 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 show.
  • They will weigh around one and a half pounds.

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.

If you've found yourself with a new baby kitten, contact our Seattle vets right away so we can help you ensure that it is on the right track toward a long and healthy life.