Kitten Age Chart
Updated
Quick answer
How old is my kitten?
You can age a kitten within about a week using weight, teeth, and eyes. Newborns weigh 3 to 5 ounces with closed eyes; teeth arrive around week 3 at about 15 ounces; by 8 weeks a kitten weighs about 2 pounds. From there, add roughly a pound per month until six months.
| Age | 1 wk | 3 wk | 8 wk | 4 mo | 6 mo |
|---|---|---|---|---|---|
| Weight | 8 oz | 15 oz | 2 lb | 4 lb | 6 lb |
How to tell how old a kitten is
Read three clocks together: weight (roughly a pound per month until six months), teeth (baby teeth erupt on a tight weekly schedule, adult teeth from about month 4), and eyes and ears (closed at birth, open by two weeks, blue until about week 9). One clue can mislead; a small kitten may just be underfed. Two or three clues agreeing usually pin the age within a week, which matters because feeding, weaning, and vaccine schedules all key off age.
Found newborns and not sure when they arrived? Our cat pregnancy calculator works the other direction, from mating date to due date. And once your kitten is grown, the cat age calculator takes over.
Kitten age chart: newborn to 12 months
| Age | Weight | Teeth | What you'll see |
|---|---|---|---|
| Newborn | 3–5 oz (85–140 g) | None | Eyes closed, ears folded, can't stand |
| 1 week | ~8 oz (225 g) | None | Eyes opening (day 6–7), ears unfolding |
| 2 weeks | ~10 oz (280 g) | None | Blue eyes open; wobbly crawling; first hisses |
| 3 weeks | ~15 oz (425 g) | Incisors erupting | Walking; litter box and wet food can start |
| 4 weeks | ~1 lb (450 g) | Canines erupting | A fluffy miniature of mom; play begins |
| 5–6 weeks | 1.25–1.5 lb (570–680 g) | Premolars erupting | Vigorous play; grooming self and littermates |
| 8 weeks | ~2 lb (900 g) | All 26 baby teeth in | Fully weaned; big enough to be neutered |
| 3 months | ~3 lb (1.4 kg) | Baby teeth | Eye color has changed from blue (from ~week 9) |
| 4 months | ~4 lb (1.8 kg) | Adult incisors arriving | Teething; lanky teenager phase |
| 5–6 months | 5–6 lb (2.3–2.7 kg) | All 30 adult teeth by 6–7 months | Near adult size; spay/neuter by 5 months |
| 12 months | Adult weight (most cats 8–12 lb) | Full adult set | Officially a cat |
Weights and early milestones follow Alley Cat Allies' kitten progression guidance1; tooth timings follow the Merck Veterinary Manual2. Individual kittens vary, and litter size, nutrition, and breed all shift the numbers.
Kitten age by teeth
Teeth are the most reliable single clock, because eruption follows a tight schedule2:
| Teeth | When they appear |
|---|---|
| Baby incisors (front teeth) | 2–4 weeks |
| Baby canines (fangs) | 3–4 weeks |
| Baby premolars | 5–6 weeks |
| All 26 baby teeth in | 6–8 weeks |
| Adult teeth start replacing baby teeth | from ~3–4 months |
| All 30 adult teeth in | 6–7 months |
The practical read: no teeth means under 3 weeks, a full set of small baby teeth means 2 to 3 months, and a mix of baby and larger adult teeth means about 4 to 6 months.
Kitten weight by age: the pound-a-month rule
A healthy kitten gains about a pound a month for the first six months: two pounds at two months, four at four. The rule is why shelters can say "2 pounds, safe to neuter" and mean "about 8 weeks old"1. Weigh on a kitchen scale (a bowl and a tare button make it easy) rather than guessing by eye, and weigh at the same time of day when tracking growth. Growth tapers from month six; most cats reach adult weight around their first birthday.
Eyes and ears: the early clock
For the first two weeks, eyes and ears tell the story best. Kittens are born with eyes closed and ears folded; eyes begin opening around day 6 and finish by about two weeks, while ears unfold across week one1. Every kitten starts with blue eyes; the adult color arrives around week 9. So blue eyes plus a wobble means weeks, and settled eye color means months.
How it works
Kittens grow on a schedule so dependable that shelters date them within a week: weight climbs by the month, teeth arrive by the week, and eyes open and change color right on cue. The chart just reads those three clocks together.
The details: weight follows the pound-a-month pattern documented in shelter guidance1, tooth eruption follows veterinary dental timelines2 (26 baby teeth between weeks 2 and 8; 30 adult teeth between months 4 and 7), and eye and ear milestones cover the first two weeks.
Life-stage labels (kitten to 1 year, then young adult) follow the 2021 AAHA/AAFP Feline Life Stage Guidelines3.
Frequently asked questions
How old is my kitten?
Check three things: weight (kittens gain roughly a pound a month for the first six months), teeth (baby teeth erupt between weeks 2 and 6, adult teeth from about month 4), and eyes (closed until about a week, blue until about week 9). The chart above matches each combination to an age within about a week.
How old does a kitten have to be to get fixed?
Shelters commonly neuter from 8 weeks and 2 pounds. For owned kittens, vets recommend spay or neuter by 5 months, before the first heat; cats can get pregnant as early as 4 months.
How much should a 4-month-old kitten weigh?
About 4 pounds (1.8 kg). The rule of thumb is a pound per month of age until about six months, so a healthy 3-month-old runs near 3 pounds and a 5-month-old near 5.
When do kittens open their eyes?
Eyes begin opening around day 6 and are typically fully open by the end of week two. Every kitten has blue eyes at first; the adult color settles in around week 9.
When do kitten teeth fall out?
From about 3 to 4 months, when the 26 baby teeth start giving way to the 30 adult teeth. Most kittens have their full adult set by 6 to 7 months. Finding a tiny tooth on the floor is normal; most are swallowed harmlessly.
When can a kitten leave its mother?
Eight weeks is the widely used minimum, once fully weaned. Ten to twelve weeks is better when possible; those extra weeks with mom and littermates build social skills that last a lifetime.
What age does a kitten become a cat?
At 12 months a kitten officially graduates to adult, though growth tapers from about 6 months. Large breeds like Maine Coons keep filling out for two years or more.
References
- 1.Alley Cat Allies. Kitten Progression: At-a-Glance. alleycat.org
- 2.Merck Veterinary Manual. Dental Development of Cats. merckvetmanual.com
- 3.American Animal Hospital Association / American Association of Feline Practitioners (2021). AAHA/AAFP Feline Life Stage Guidelines. aaha.org
