Kitten Development: Understanding a Kitten's Major Growth Milestones

The first eight weeks of a kitten’s life are a whirlwind of developmental changes. As newborns, kittens are defenseless, blind, and fit in the palm of your hand. But by 8 weeks of age, they’re running, playing, and looking like miniature cats.

Each week, the kitten will have different needs in terms of feeding, bathroom help, medical support, and warmth. It’s important to know how to identify a kitten’s age, as this determines what care the kitten needs and whether the kitten is developing normally.

Here’s what you need to know about the developmental milestones of a kitten’s first eight weeks of life. 

Kitten Age Chart

Newborn Kittens

Average weight: 1.8–5.3 ounces (50–150 grams)

Physical Development

Newborn kittens will have their eyes closed and their ears folded. They will have no teeth and their gums, nose, and paws may appear bright pink in color. They do not yet have a gag reflex or the ability to thermoregulate.

The umbilical cord will be attached and will fall off on its own around 4 to 5 days of age. Their claws will be non-retractable.

At this age, they cannot hear or see; they can only navigate the world around them through scent and through seeking warmth and comfort.

Behavioral Development

Newborns will sleep for the majority of the day. Newborn kittens cannot defend themselves or walk, but they may be able to move around by crawling. A healthy newborn will wiggle and meow if handled.

Average Temperature

A kitten’s temperature should be 95–97 degrees Fahrenheit at birth. It is critical to provide a gentle heat source to keep the kitten warm and stable. The kitten's environment should be kept between 85–90 degrees at this time.

Care

Newborn kittens belong with their mother full-time. The mother will provide them with food, cleaning, warmth, and bathroom support.

If no mother is present, they must be fed with a bottle and kitten formula every two hours by a knowledgeable caregiver, stimulated to go to the bathroom, and kept at an appropriate temperature.

1-Week-Old Kittens

Average weight: 5.3–8.8 ounces (150–250 grams). By 1 week of age, the kitten should have roughly doubled their birth weight.

Physical Development

One-week-old kittens will still have their eyes closed, but no umbilical cord. They will still have no teeth, and their claws will still be non-retractable. At around 7 days old, the ear canals will slowly begin to open and the ears will slightly unfold.

At 8–12 days old, the eyes will slowly begin to open, which can occur over the course of several days. One eye may open more quickly than the other; it’s important to let the kitten’s eyes open at their own pace. All kittens will be born with blue eyes, which will transition to an adult eye color with age.

Behavioral Development

One-week-old kittens, though larger than newborns, will still be mostly uncoordinated and will similarly sleep for the majority of the day. At this age, they should be able to hold their head up, move by wiggling their limbs, and be active and vocal if handled.

Average Temperature

At this age, kittens should be 97–98 degrees F. It is critical to provide a gentle heat source to keep the kitten warm and stable. The kitten's environment should be kept around 85 degrees at this time.

Care

One-week-old kittens belong with their mother full-time. If no mother is present, they must be fed with a bottle and kitten formula every two to three hours by a knowledgeable caregiver, stimulated to go to the bathroom, and kept an appropriate temperature.

2-Week-Old Kittens

Average weight: 8.8–12.3 ounces (250–350 grams)

Physical Development

At 2 weeks of age, kittens' eyes will be fully open and baby blue. Their vision will be poor, and they will not be able to see at long distances. The ear canals will be open, and the ears will be small and rounded, like a bear cub.

If you open the kitten’s mouth, you will find that there are still no teeth. Their claws will still be non-retractable.

Behavioral Development 

Two-week-old kittens are becoming more coordinated and will be beginning to attempt their first steps. But they will be wobbly on their feet and uncoordinated.

Kittens at this age may exhibit some curiosity about the world around them, will not yet be playing, and will spend the majority of their time sleeping.

Average Temperature

Kittens should be 98–99 degrees F. It is critical to provide a gentle heat source to keep the kitten warm and stable. The kitten's environment should be kept around 80 degrees at this time.

Care

Two-week-old kittens belong with their mother full-time. If no mother is present, they must be fed with a bottle and kitten formula every three to four hours by a knowledgeable caregiver, stimulated to go to the bathroom, and kept an appropriate temperature. Two-week-old kittens may begin a dewormer.

3-Week-Old Kittens

Average weight: 12.3–15.9 ounces (350–450 grams)

Physical Development

At 3 weeks of age, kittens will have blue eyes and small ears that are beginning to point upward, like a miniature cat. The kitten’s vision and hearing will be slowly improving.

At this age, a kitten's first baby teeth will begin to emerge. The tiny teeth at the front of the mouth, called the incisors, will start to come through the gums. Kittens will slowly begin retracting their claws.

Behavioral Development

At this age, kittens will be walking, exploring their surroundings, and even beginning to explore the litter box. They may begin to become curious about cat toys, though they are not yet able to run or chase after moving objects.

They will sleep frequently and may begin some small self-grooming behaviors. During this week, their coordination will be improving rapidly.

Average Temperature

Three-week-old kittens will be 99–100 degrees F. They still require a heat source but will be more active and may stray from it when not sleeping. The kitten's environment should be around 75 degrees at this time.

Care

Three-week-old kittens belong with their mother full-time. If no mother is present, they must be fed with a bottle and kitten formula every four to five hours by a knowledgeable caregiver. Introduce a shallow cat litter box with a non-clumping litter, and monitor them to make sure they don’t try to eat the litter.

4-Week-Old Kittens

Average weight: 15.9 ounces–1.2 pounds (450–550 grams)

Physical Development

At 4 weeks of age, kittens will have much improved vision and hearing. The kitten's teeth will continue to develop; the long teeth next to the incisors, called the canine teeth, will start to come through the gums. Their claws will be retractable.

Behavioral Development

Four-week-old kittens will be confidently exploring and developing more coordination that allows them to walk, run, and even begin to play. With their improved senses, they will be notably more responsive, making frequent eye contact with caregivers and reacting to sights and sounds in the environment.

Their grooming skills may still be limited but improving. They will be starting to use a litter box.

Average Temperature

Four-week-old kittens will be 99–101 degrees F. Continue providing a heat source, although they will likely use it only when resting. The kitten's environment should stay comfortably warm and never colder than 70–75 degrees.

Care

Four-week-old kittens belong with their mother full-time. Orphans of this age should be bottle fed every five hours, including overnight. Four-week-old kittens will generally be using the litter box and can begin to be introduced to toys.

5-Week-Old Kittens

Average weight: 1.2–1.4 pounds (550–650 grams)

Physical Development

At 5 weeks of age, a kitten's baby teeth will continue to develop and the premolars will start to emerge. Their eyes will be blue, ears will be growing and pointed, and claws will be retractable.

Behavioral Development

Five-week-old kittens will be running and playing confidently. They will be developing social skills with humans and other animals. Their grooming skills will be improving. They will have perfected their use of the litter box by this age.

Average Temperature

Kittens will be 100-101 degrees F at this age. A heating source is no longer required as long as the environment is a comfortable temperature of 70–75 degrees.

Care

Five-week-old kittens, if healthy, may begin the weaning process. Kittens should receive ample “slurry” or kitten wet food, in addition to access to their mother’s milk or, if orphaned, a bottle.

If weaned, food and water should be provided at all times. Always provide supplemental feeding and ensure that the kitten is maintaining a healthy weight and body condition during weaning. Provide a shallow litter box at all times.

6-Week-Old Kittens

Average weight: 1.4–1.7 pounds (650–750 grams)

Physical Development

At 6 weeks of age, a kitten's baby teeth will begin to reach their final stage of early development. The molars will start to emerge. The eyes will still be blue, and vision and hearing will be fully developed.

Behavioral Development

Six-week-old kittens will be socializing confidently with peers, play-fighting, pouncing, and defending themselves. They will be curious about their surroundings and eager to explore. They will be perfecting their grooming skills. Six-week-old kittens are becoming coordinated enough to jump off short furniture and land on their feet.

Average Temperature

Six-week-old kittens will be 100–101 degrees F. At this age, a heating source is no longer required as long as the environment is a comfortable temperature of 70–75 degrees.

Care

Kittens at this age should be receiving ample kitten wet food, though they might not be completely weaned yet. Provide access to water, food, and a shallow litter box at all times. At six weeks, kittens can receive their first FVRCP vaccine to protect them against viruses (rhinotracheitis, calicivirus, and panleukopenia).

7-Week-Old Kittens

Average weight: 1.7–1.9 pounds (750–850 grams)

Physical Development

All baby teeth will be present at 7 weeks of age. The kitten’s eye color will be changing, and the adult eye color will begin to emerge. Male kittens’ testicles may begin to descend around 7 weeks.

Behavioral Development

Seven-week-old kittens will experience a spike in energy. Sleep will decrease and time spent playing will increase. At this age, kittens are able to run, climb cat trees, and confidently jump off of furniture.

Average Temperature

Seven-week-old kittens will be 100–101 degrees F. At this age, a heating source is no longer required as long as the environment is a comfortable temperature of 70–75 degrees.

Care

Kittens should receive ample kitten wet food, and may have kitten dry food as a supplement. Provide access to water, food, and a shallow litter box at all times.

8-Week-Old Kittens

Average weight: 1.9–2.1 pounds (850–950 grams)

Physical Development

All baby teeth will be present at 8 weeks of age. The eyes will be completely transitioned to their adult color of green, yellow, brown, or blue. The ears will be proportionate.

Behavioral Development

Eight-week-old kittens will be energetic and independent. Their agility and coordination will be nearly fully developed.

Average Temperature

Kittens at this age will be 100–101 degrees F. A heating source is no longer required as long as the environment is a comfortable temperature of 70–75 degrees.

Care

Kittens should receive access to canned and dry kitten food three to four times per day, and they can receive the bulk of their calories from dry food if they choose. Provide access to water and a shallow litter box at all times.

If two weeks have passed since their first FVRCP vaccine, kittens may receive a booster at this time. If the kitten has not been dewormed, oral dewormer can be administered. It is also a good idea to have a fecal test run to check for internal parasites.

At this age, if they are 2 pounds and healthy, they may be spayed/neutered, microchipped, and adopted. 

When Is a Cat Fully Grown?

Cats are typically considered fully grown at about 9 months of age, when their adult canine teeth (the fang teeth) have grown in and they have reached their mature size, which averages 8–10 pounds. 

At this stage, they will still have a lot of energy and kitten behaviors, such as climbing furniture and chasing feet, but physically they’re well on their way to maturity.