The needs of a kitten from birth to eight weeks changes rapidly, which is why it is so important to be able to determine just how old they are. Our La Mesa vets have crafted foolproof ways to help you figure out your tiny kitten's age.

Why It Is Important To Know A Kittens Age

If you ever rescue a kitten, it is crucial you know how old it is in order to properly care for it. Each week of a kitten's life from birth to about eight weeks marks an important milestone in their development and comes with a new set of needs. The needs of a 1-week-old kitten will be very different from the needs of a 4-week-old kitten.

How To Tell A Kittens Age In 4 Easy Steps

While we will get into more detail later in the post, here are 4 simple steps you can follow to get a pretty good estimate of your kitten's age.

1. Look at their teeth

Here is how to tell a kitten's age by its teeth. Baby teeth start to come in around 3 weeks of age and permanent teeth at 3-4 months. The middle incisors are the first to come in around 14 weeks, with the second and third incisors following at about 15 and 16 weeks, respectively.

Kitten teeth are tiny, which makes it tricky to tell if the incisors are baby or permanent. It’s easiest when you have some of both to serve as a comparison. The baby teeth are a little smaller with pointed tips, while permanent teeth are a little wider with flat edges.

    2. Check your kitten's weight

    A healthy kitten should be gaining weight at a relatively predictable rate until they are about five months old. Each week of life should correspond to at least a 100 gram increase in weight. If a newborn kitten weighs about 50-150 grams, that same kitten should weigh 150-250 by the end of its first week of life. By the end of the second week, it should weigh 250-350 grams, and so on.

    3. Have they opened their eyes

    Kittens are born with their eyes closed, and they don’t open until about 10 days of age. When a kitten first opens its eyes, they will be blue. It is likely the cats eyes will change color as it matures.

    4. Do they walk around or play

    Most kittens start walking around 3 weeks of age but take a little longer to gain their coordination. You can be comfortable saying a kitten who is walking pretty well and playing is at least 4 weeks of age.

    Development & Behavioral Milestones

    To get the most accurate age for your new kitten, you'll likely have to have them checked by a vet during their first veterinary checkup. Here are a number of milestones that you can look out for to get a more accurate determination, use it like a "kitten age chart".

    New Born

    • Still have their eyes closed, their ears folded and the umbilical cord still attached.
    • They are still unable to see or hear the world around them.
    • Nose and paws may be pink in color.
    • Weight roughly 50-150 grams.
    • Low body temperature, usually around 95-97 degrees.

    One Week Old

    • Eyes are still closed and they have no umbilical cord.
    • At about 7 days their ear canals will begin to open.
    • Around 8-12 days, the eyes will slowly begin to open. Never attempt to pry open a kitten's eyes; let them open naturally.
    • By one week of age, the kitten should have doubled her birth weight (approximately 150-250 grams).

    Two Weeks Old

    • At two weeks of age, the kittens' eyes will be fully open and baby blue. Her vision will still be developing.
    • The ear canals will be open and the ears will be small and rounded, like a baby bear cub.
    • Two-week-old kittens will be wobbly on their feet and attempting to develop coordination and movement.
    • A two-week-old kitten should weigh anywhere from 250-350 grams.

    Three Weeks Old

    • At three weeks of age, a kitten's first teeth will begin to emerge. The tiny teeth at the front of the mouth, called the incisors, will start to come through the gums.
    • Three-week-old kittens will have ears that point upwards, like a miniature cat.
    • At this age, kittens will be walking, exploring their surroundings, and even beginning to explore the 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 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 anywhere from 350-450 grams.

    Five Weeks Old

    • The premolars will start to emerge, indicating that a kitten is ready to be introduced to weaning onto wet food.
    • Your kitten should now weigh roughly 550-650 grams.

    Six Weeks Old

    • At six weeks of age, a kitten's deciduous teeth will have fully emerged, and they are ready to begin weaning onto wet food.
    • At this stage, your kitten can weigh 650-750 grams.

    Seven Weeks Old

    • At seven weeks, 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 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.
    • They will weigh in around 750-850 grams.

    Eight Weeks Old

    • At eight weeks old, most kittens will be eating independently.
    • Kittens of this age will have their permanent adult eye color.
    • Your kitten should weigh about 850-950 grams.

    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 come across a kitten that needs veterinary care contact our La Mesa vets right away