Have you just rescued a kitten and are unsure of its age?

Being able to swiftly determine kitten age is a valuable skill for any kitten rescuer or fosterer.

It can even be a matter of life and death.

How?

The needs of a one-week-old kitten are very different from those of a four-week-old. If you misjudge a newborn kitten and treat it like a one-month-old, you might endanger its life.

So, to help you correctly understand the age of a kitten, I’m sharing the key physical features and behavioral traits of kittens from newborn to 8 weeks old. 

And once you figure out the age of your kitten, be sure to download my free resource – The Beginner’s Handbook to Fostering Kittens. It’s filled with week-by-week support, real-life advice, and pro tips to help you raise healthy, thriving kittens.

Newborn Kitten (Less Than 1 Week Old) 

• Eyes closed
• Ears folded down
• Umbilical cord attached
• Average weight: 50-150 grams

Appearance Of A Newborn Kitten

A kitten under one week old will have its eyes closed and ears folded down. This is because a kitten’s senses continue to develop after birth. 

Kittens’ umbilical cords typically stay attached for the first 3 to 5 days, sometimes up to one week. So, if the kitten you’ve found still has theirs attached, they are less than one week old. 

A wet umbilical cord indicates that they were born very recently. A dried cord like the one Grizzly has in this photo shows he is more than a couple of days old.

They are incredibly tiny at this age (less than 100g) and often look more like mice than kittens!

Behavior Of A Newborn Kitten

In the first week of life, a kitten is busy developing its internal organs. So they will spend almost all their time sleeping, and you might have to wake them up for their bottle feeding sessions.

As their senses develop, newborn kittens will not respond so much to sounds or bright lights. 

What You’ll Need For A Newborn Kitten

• Kitten formula – KMR Kitten Milk Replacer Powder is my go-to as I find it’s the most gentle on tiny stomachs.
• Feeding bottles or syringes – This kitten feeding set has multiple syringes and nipples so is perfect for newborns who only need a few ml per feeding.
• Digital kitchen scale – Weigh daily to ensure they’re gaining consistently.
• Pet-safe heating pad – Keeping their body temperature stable is critical!
• Cotton balls or tissues – Newborn kittens are unable to pee and poop on their own, so you need to stimulate them after each feeding.

1 – 2 Week Old Kitten

• Eyes starting to open
• No umbilical cord
• Average weight: 150-250 grams

Appearance Of A 1 – 2 Week Old Kitten

By one week old, the umbilical cord will have fallen off.

As you can see from this photo of one-week-old Scooby, his eyes are starting to open. This can occur at any time between 8 and 12 days, and it usually takes a few days for them to open fully.

Also, one eye can open before the other one. During this stage, their vision remains poor.

At this kitten age, you might also notice the kitten’s ears starting to unfold as their hearing improves. 

Behavior Of A 1 – 2 Week Old Kitten

As the kitten’s senses slowly improve, they appear more aware and responsive to your voice. So, if you speak to them before you pick them up, you will likely find they start stirring from the sound of your voice.

However, a one to two-week-old kitten is still growing and developing rapidly. So they will continue to spend all their time sleeping.

What You’ll Need For A 1 – 2 Week Old Kitten

• Kitten formula like KMR Kitten Milk Replacer Powder.
• Feeding bottles or syringes – This kitten bottle set has different nipple sizes and shapes for the kitties that are difficult to feed!
• Digital kitchen scale – Weigh them daily to ensure they’re gaining consistently.
• SnuggleSafe heat disc – A pet-safe heat source that stays warm for up to 10 hours.
• Cotton balls or tissues – To stimulate peeing and pooping after each feeding.

2 – 3 Week Old Kitten

• Eyes fully open
• Blue color eyes
• Ears unfolding
• Starting to move around
• Average weight: 250 – 350 grams

Appearance Of A 2 – 3 Week Old Kitten

By two weeks old, the kitten’s eyes will be fully open and a deep blue color, like Scooby’s are in this photo. A kitten’s ears also unfold between two and three weeks old but remain small and rounded. 

Behavior Of A 2 – 3 Week Old Kitten

Between 2 and 3 weeks, you will notice the kitten starting to move around. While they cannot walk, they will roll around on their back. They might also attempt crawling (although they will be unable to take more than a couple of steps before falling).

If you’ve been raising a kitten from birth, you’ll notice they now start to spend more time awake. 

When you come to feed them, you might see them staring into space. And after feeding, rather than go straight back to sleep, you might see them rolling on their back, pawing the air, which is incredibly cute!

What You’ll Need For A 2 – 3 Week Old Kitten

• Soft fleece blankets – Helps keep them warm and comforted as it feels like their mama’s fur.
• Soft-bristle toothbrush – To introduce gentle grooming.
• Kitten formula – At this age, they should be feeding every 3 -4 hours.
• Bottle feeding kit – You may need to increase nipple hole size slightly as they get stronger.

3 – 4 Week Old Kitten

• Ears fully open and pointed up 
• First teeth (incisors) emerging 
• Becoming more active
• Average weight: 350 – 450 grams

Appearance Of A 3 – 4 Week Old Kitten

This is the age when kittens start to look (and act) like baby cats. As you can see from this photo of Grizzly, he is now looking like the cute and fluffy kitten we know and love.

At around three weeks old, a kitten’s first teeth emerge. 

However, this does NOT mean they are ready to eat wet food. The only teeth that come through at this age are the incisors (the tiny teeth at the front of the mouth), which are for grooming, not eating.

The kitten’s ears will also look more pointed and rounded and appear more proportionate to their head.

Behavior Of A 3 – 4 Week Old Kitten

At this age, kittens start to become more active. With their senses fully developed and their muscles and bones stronger, they start to explore their surroundings. They will begin to walk but will still be wobbly, falling often. 

Towards the end of week three, you might notice the kitten making use of its first teeth by attempting to groom itself – an utterly adorable moment!

Another significant milestone of this kitten age is going to the toilet independently! So around this time, you will likely notice they’ve peed and pooped on their own in between feedings. 

As soon as they can potty on their own, they can learn to use the litter box. However, their tiny brains may need several days to comprehend this new technique. 

What You’ll Need For A 3 – 4 Week Old Kitten 

• Shallow litter tray – Kittens this age may start to pee and poop on their own.
• Kitten-safe wipes – To clean up the inevitable accidents during litter box training.
• A small playpen – They will want to explore more so a playpen will give them room to move while keeping them safe.

4 – 5 Week Old Kitten

• More teeth (canines) emerging
• More stable and confident on their feet
• Using litter tray
• Average weight: 450-550 grams

Appearance Of A 4 – 5 Week Old Kitten

Between 4 and 5 weeks old, you will notice the kittens’ canines coming through, although their baby canines are tiny! While the canines are designed to rip into meat, they don’t yet have their teeth for chewing (premolars). 

However, this is usually when I slowly introduce food to their diet by making “meat shakes” (blending formula with wet kitten food).

By this age, a kitten is also able to retract its claws. Kittens less than four weeks old will have permanently extended claws.

Behavior Of A 4 – 5 Week Old Kitten

By four weeks old, a kitten is pretty stable on its feet, although it might still fall occasionally. They can go in and out of the little tray with no problem if the opening is not too high. 

This is the start of the fun kitten age, as they interact with you more and begin playing.

What You’ll Need For A 4 – 5 Week Old Kitten 

• High-quality kitten wet food like Royal Canin Mother & Baby Cat – Begin introducing a formula+wet food (gruel) combo.
• Kitten food bowls – Choose shallow dishes that are easy to reach.
• A variety of kitten toys – Start developing their play instincts.
• Pet-safe disinfectant – More movement means more mess!

5 – 6 Week Old Kitten

• Final teeth (premolars) emerging
• Starting to eat solid food
• Running and playing
• Average weight: 550 – 650 grams

Appearance Of A 5 – 6 Week Old Kitten

A kitten gets their final teeth between five and six weeks old – the premolars in the back of the mouth. This is also the age when kittens look well-proportioned. Their legs are straighter so their belly does not hang as close to the floor.

Behavior Of A 5 – 6 Week Old Kitten

5 to 6-week-old kittens are typically playful and active. While they still take lots of naps, they will also have many play sessions and be super curious.

However, the most significant milestone of this kitten age is weaning. 

Now that the kitten has its complete set of teeth, they can start to eat wet kitten food. However, you should still supplement them with milk throughout the weaning period (which should last until eight weeks old). 

As a kitten learns to eat food, you might see them “meat-nursing.” This is when they get stuck in a trance, suckling the food rather than eating it. 

What You’ll Need For A 5 – 6 Week Old Kitten 

• High-quality kitten wet food like Royal Canin Mother & Baby Cat – Increase the amount of wet food and decrease the formula qunatity.
• Small scratching post or pad – Introduce good scratching habits early!
• Wand toys – Great for burning off energy and encouraging coordination.

6 – 8 Week Old Kitten

• Has full set of teeth
• Eyes transition to adult color
• Eating independently 
• Average weight: 650 – 900 grams

Appearance Of A 6 – 8 Week Old Kitten

A kitten’s development starts to slow by six weeks old as they have reached all their major early milestones. Even so, their weight should rapidly increase as they start eating wet food, which is much denser in calories. 

Around seven weeks old, the kitten’s eyes might start to transition from blue to its permanent adult color, but this can happen later in some kittens.

Behavior Of A 6 – 8 Week Old Kitten

Throughout these two weeks, a kitten starts eating independently. By eight weeks old, they should be able to eat wet food from a bowl without making too much mess! They may or may not be able to eat dry food at this age.

Kittens between 6 and 8 weeks old are energetic, always running around and playing. This is a good age to introduce interactive play, such as getting them to chase fake prey on strings. 

At 8 weeks old, kittens can also receive their first core vaccination.

What You’ll Need For A 6 – 8 Week Old Kitten 

• Kitten wet food like Royal Canin Mother & Baby Cat – They will be in the final stages of weaning now.
• Kitten kibble like Royal Canin Mother & Baby Cat Dry Food – Now they have a full set of teeth you can introduce kibble. Moisten it to start with.
• Small cat tree – Get them climbing, scratching, and exploring vertically.
• Kitten grooming brush – You can start brushing them now to build a regular grooming habit.

A Note On Kitten Age & Development

To demonstrate how a kitten should look at each milestone, I’ve created a kitten age chart using photos of two of my previous foster kittens, Grizzly and Scooby, whom I raised from birth.

Note that this kitten age chart (and the milestones and weights of the kitten stages mentioned above) is just a guideline. Every kitten’s development is different.

I find that stray kittens orphaned at a very early age (such as in their first week of life) struggle to meet all their milestones promptly and often grow slower. So bear this in mind if you raise a newborn kitten without a mother.

That said, if you’re caring for an orphaned kitten and are concerned about its development, do NOT hesitate to see a vet ASAP. 

Kittens under two months old are incredibly vulnerable. If they become sick, they can deteriorate rapidly and die if they don’t receive prompt medical care.

How To Tell The Age Of A Kitten Older Than 2 Months

As kittens tend to reach all their most noticeable milestones in the first eight weeks, determining the age of kittens older than two months is more complicated.

Weight is not an accurate determinator as many things, such as genetics and upbringing, will determine their weight. 

So, the surest way to “age” a kitten is to take it to your local veterinarian, who can estimate the kitten age by teeth. 

Kittens typically lose their baby teeth between three and four months old and usually have their complete set of adult teeth by 6 or 7 months old. Kitten baby teeth are smaller and sharper than their permanent adult teeth.

Next Steps

So, if you’ve just found a stray kitten and determined its age, what should you do next?

I’ve created a FREE resource to walk you through how to care for a newborn kitten from 0 to 8 weeks old and beyond.

The Beginner’s Handbook to Fostering Kittens is filled with week-by-week support, real-life advice, and pro tips to help you raise healthy, thriving kittens.

Download it here:

FAQs

How old is a kitten when it opens its eyes?

Kittens typically open their eyes between 8 and 12 days. However, their eyes usually open over the course of a few days.

How to tell the age of a kitten by teeth

Kittens get their first teeth (incisors) between 3 and 4 weeks old. These are the tiny teeth right at the front of the mouth. They they get their sharp canines between 4 to 5 weeks old and their back teeth (premolars) between 5 and 6 weeks old.

How to determine kitten age by weight

• Newborn to 1 week old kitten: 50-150 grams
• 1 – 2 week old kitten: 150 – 250 grams
• 2- 3 week old kitten: 250 – 350 grams
• 3- 4 week old kitten: 350 – 450 grams
• 4- 5 week old kitten: 450 – 550 grams
• 5 – 6 week old kitten: 550 – 650 grams
• 6 – 8 week old kitten: 650 – 900 grams