Last Updated: 03/06/2026
Kitten Stages of Development: A Week by Week Guide (0 to 12 Weeks)
Your week-by-week vet guide to kitten development from 0 to 12 weeks, and how to tell their age.
Author: Dr Gillian Hill BVSc (Hons)
Reading Time: 5 minutes - short read
Whether you are watching a litter grow up or trying to work out how old the kitten you have just taken in actually is, knowing what is normal at each age makes those first weeks far less daunting. Kittens change enormously between birth and twelve weeks, going from blind, helpless newborns to confident, playful little characters ready for a new home. Here is what happens at each of the kitten stages of development, and how to tell where yours is up to.
This guide is your overview of the whole first twelve weeks. Each stage links out to a more detailed guide if you want to go deeper.
What are the kitten stages of development?
Kittens develop in four broad stages over their first twelve weeks. Each one brings big changes in how they look, move and behave.
- Neonatal (0 to 2 weeks): Eyes and ears closed, fully dependent on mum
- Transitional (2 to 3 weeks): Senses switch on, first teeth and wobbly steps
- Socialisation (2 to 7 weeks): Weaning, play, and the experiences that shape adult temperament
- Early juvenile (8 to 12 weeks): Independent, confident, ready to go home
Kittens move through four developmental stages in their first twelve weeks, neonatal (0 to 2 weeks), transitional (2 to 3 weeks), socialisation (2 to 7 weeks) and early juvenile (8 to 12 weeks). The socialisation window is the most influential for a cat's adult temperament. In other words, the weeks before a kitten even comes home matter just as much as the ones after.
Kitten development week by week
Most of the change happens fast. Kittens are born blind, deaf and unable to keep themselves warm or toilet without their mother's help. Their eyes open from around 7 to 10 days.
Through weeks two and three (the transitional stage) their ears unfold, their first baby teeth come through and they take their first wobbly steps.
From about two weeks the all-important socialisation stage begins. Kittens start weaning from around four weeks, learn to use a litter tray, and begin playing, wrestling and learning bite inhibition with their littermates.
By eight to twelve weeks they are fully weaned, well coordinated and bursting with energy. This is the usual age to go to a new home. Our 8-week-old kitten guide covers what to expect when they do.
If you are hand-rearing a kitten this young, our guide to caring for a newborn kitten covers feeding and warmth in detail, and you can read more about that critical early window in our kitten socialisation guide.
Week 1
- Eyes and ears closed
- No teeth
- Average 100g at birth
- Gaining an average of 10-15g per day, should double birth weight by day 7-10
- Sleeping and feeding
- Needs mum for everything, including stinulation to toilet until around 3 weeks of age
Week 2
- Eyes and ears start to open
- No teeth
- 270 to 305g bodyweight
- Beginning to crawl
Week 3
- Eyes and ears working
- First baby teeth - incisors erupting
- 340 to 410g bodyweight
- First steps
- Starts lapping
Week 4
- Full blue eyes
- Canine teeth erupting
- Around 450g bodyweight
- Walking
- Playing
- Exploring
Weeks 5 to 6
- Eye colour may start to change
- Premolars start erupting
- 550 to 700g bodyweight
- Weaning
- Using the litter tray
Weeks 7 to 8
- Adult eye colour developing
- Full set of baby teeth
- 800 to 900g bodyweight
- Confident
- Very playful
- Fully weaned
Weeks 9 to 12
- Eyes and ears as adult
- Adult teeth from around 12 weeks
- 1 to 1.5kg
- Independent, ready for a new home
Weight is a rough guide only, and can vary by breed, litter and mum-raised vs hand-raised kittens. There is also usually an undersize kitten in each litter that will fall below the listed averages.
How can I tell how old my kitten is?
If a kitten has arrived without a clear history, a few physical clues give you a good estimate:
- Under 1 week: eyes and ears still closed, unable to move around much.
- 1 to 4 weeks: eyes and ears open, movement wobbly and unsteady.
- 4 to 6 weeks: walking confidently, starting to play, baby teeth coming through.
- 6 to 8 weeks: a full set of baby teeth, eating some solid food, and from around 6 weeks the eyes begin shifting from kitten-blue towards their adult colour.
Weight is another rough guide, since kittens gain roughly 100g a week, though this varies with breed and health. If you are unsure, your vet can age your kitten more precisely and check they are developing as they should.
When can a kitten leave its mother?
Kittens should not leave their mother and littermates before eight weeks of age (in most states and territories there are Codes of Practice legislating this), and many vets and behaviourists recommend waiting until later than this. Those extra few weeks matter because they let a kitten:
- Finish weaning fully onto solid food.
- Learn bite inhibition, so they are gentler with their mouth and claws.
- Pick up how to read and get along with other cats.
- Build the social skills that are hard to learn later on.
RSPCA Australia considers eight weeks the minimum, and leaving too early is associated with behavioural issues such as nervousness and poor litter habits. Whatever age yours comes home, our New Kitten Checklist walks through settling them in and booking those first kitten vaccinations.
The lively, into-everything phase that follows is normal kitten behaviour. If your kitten is biting, pouncing and testing boundaries, our guides to stopping a kitten biting and normal kitten behaviour will help, and our 3-month-old kitten guide covers what to expect as they grow.
Kitten Development FAQs
A kitten's first twelve weeks pack in a remarkable amount of change, from a blind, helpless newborn to a confident young cat ready to explore the world. Knowing what is normal at each stage helps pet parents tell whether a kitten is developing on track, work out the age of a kitten of unknown history, and understand why those early weeks with mum and littermates matter so much. If anything seems off for your kitten's age, a quick chat with your vet is always worthwhile.
Where to next?
This guide is the overview. For more detail on any stage, head to the guide that matches your kitten's age:
- Caring for a newborn kitten, for hand-rearing the very young
- Kitten socialisation, for the critical two-to-seven-week window
- 8-week-old kitten, for the usual going-home age
- 3-month-old kitten, for the lively, into-everything stage
- When do kittens stop growing, for size and weight as they mature
- New Kitten Checklist, for settling in, health admin and what you need
References
RSPCA Australia Knowledgebase, How old should a kitten be before they are adopted/purchased?, kb.rspca.org.au (accessed 2 June 2026)
International Cat Care, Bringing up a litter of kittens: behavioural considerations, icatcare.org (accessed 2 June 2026)
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History
Our experts continually monitor the health and wellness space and we update our articles when new information becomes available.
Tue 2 Jun 2026
Written by Dr Gillian Hill BVSc (Hons)Dr Gillian Hill BVSc (Hons)
Veterinarian
Dr. Gillian graduated from the University of Sydney in 2005 with a Bachelor of Veterinary Science. She worked in a number of small animal clinics, before joining the Pet Circle Vet team in 2020. Dr. Gillian has special interests in ultrasonography, surgery and behaviour. Her favourite part of being a vet is being an advocate for the animals. She loves helping owners to make the best, evidence-based decisions for their pets, and seeing the beautiful bond that people have with their fur-babies.
