Kitten Age Chart: Weeks & Months in Human Years
How old is a 6-week-old kitten in human years? Full chart from 1 week to 12 months, with the milestone that tells you which age you are looking at.
Kittens age faster in their first year than at any other point in their lives. A single month is worth roughly a human year at the start, and by their first birthday they are the equivalent of a 15-year-old. That is why a chart in weeks and months is far more useful than one in years.
Know the exact age?
Enter your kitten's age in years and months for a precise human-year figure and life stage.
Open Cat Age CalculatorQuick answers
- • A 6-week-old kitten is about 18 months in human terms.
- • A 2-month-old kitten is about 2 years.
- • A 3-month-old kitten is about 4 years.
- • A 6-month-old kitten is about 10 years.
- • A 9-month-old kitten is about 13.5 years.
- • A 1-year-old cat is about 15 years.
Kitten age chart: the first 12 weeks
The first three months are mostly about development rather than human-year comparisons — a two-week-old kitten is a newborn in any species. The milestones are what let you place an age:
| Kitten age | Human equivalent | What is happening |
|---|---|---|
| 1 week | Newborn | Eyes and ears still closed; sleeping and feeding only |
| 2 weeks | Newborn | Eyes opening, blue at first; first wobbly standing |
| 3 weeks | ~9 months | Ears upright, baby teeth pushing through, first steps |
| 4 weeks | ~1 year | Walking confidently, starting to explore and play |
| 6 weeks | ~18 months | Weaning onto solid food; play-fighting with littermates |
| 8 weeks | ~2 years | Fully weaned, litter trained, first vaccinations due |
| 10 weeks | ~3 years | Confident, very active; second vaccinations due |
| 12 weeks | ~4 years | Baby teeth complete; the ideal age to go to a new home |
Kitten age chart: months to human years
From one month onwards the conversion settles into a pattern. The first year is worth about 15 human years in total, but it is not spread evenly — the early months count for far more than the later ones:
| Kitten age | In human years | Milestone |
|---|---|---|
| 1 month | 1 year | Eyes and ears fully open; starts walking |
| 2 months | 2 years | Weaned, litter trained, first vaccinations |
| 3 months | 4 years | Baby teeth complete; ready to rehome |
| 4 months | 6 years | Adult teeth start pushing through |
| 5 months | 8 years | Rapid growth; neutering window opens |
| 6 months | 10 years | All adult teeth in; near sexual maturity |
| 7 months | 11 years | Adolescent energy peaks |
| 8 months | 13 years | Roughly teenage in behaviour |
| 9 months | 13.5 years | Close to adult height and frame |
| 10 months | 14 years | Growth slows noticeably |
| 11 months | 14.5 years | Almost fully grown |
| 12 months | 15 years | Officially an adult cat |
After the first birthday the maths gets simpler: year two adds another 9 human years, and every year after that adds 4. The full cat years chart covers ages 1 to 25.
How to tell a kitten's age when nobody knows it
Found a kitten, or adopted one with no history? Four things give the age away, and teeth are the most reliable of them.
Teeth
Baby teeth start pushing through at around 2–4 weeks and the full set of 26 is in by 8 weeks. Adult teeth begin replacing them at 3–4 months, starting with the front incisors, and all 30 adult teeth are usually through by 6–7 months. Clean, white, sharp adult teeth mean a young adult rather than a kitten.
Eyes
Kittens are born with their eyes shut and open them at 7–14 days. All kittens start with blue eyes; the adult colour comes in between 6 and 8 weeks. Blue eyes on a kitten mean nothing about breed — they mean it is under two months old.
Weight
A healthy kitten puts on roughly 100 g a week for the first few months, so weight is a decent cross-check: about 450 g at 4 weeks, 900 g at 8 weeks, and around 1.4 kg at 12 weeks. It is less reliable than teeth because an underfed or sick kitten will be light for its age.
Behaviour and movement
At three weeks kittens wobble. At six they charge around and wrestle. At twelve they are fast, coordinated and into everything. A kitten that can jump onto furniture reliably is past the eight-week mark.
Found a very young kitten? Kittens under four weeks cannot regulate their own temperature or eat solid food, and they need feeding every few hours. Get them to a vet or a rescue the same day rather than working from a chart — at that age, hours matter.
What the age tells you to do next
- Under 4 weeks: bottle feeding and warmth, ideally with help from a vet or rescue.
- 4–8 weeks: weaning onto kitten food, litter tray training, and staying with the mother and littermates.
- 8–12 weeks: first and second vaccinations, first worming, and the start of proper socialisation.
- 4–6 months: the usual neutering window, and the months when adult teeth come through.
- 10–12 months: switch from kitten food to adult food, and recalculate portions — growing kittens eat far more per kilo than adults.
For portions at each stage, the cat food calculator has kitten settings built in, and how to tell a cat's age covers the same detective work for adult cats.
The bottom line
One kitten month is worth roughly one human year at the start, slowing as the first birthday approaches — 6 months is about 10 in human terms, and 12 months is about 15. If the age is unknown, count the teeth first and check the weight second. And once your kitten passes its first birthday, the cat age calculator takes over. 🐱
Frequently Asked Questions
How old is a 2 month old kitten in human years?
A 2-month-old kitten is roughly a 2-year-old child. It has just been weaned, is using a litter tray, and is due its first vaccinations. This is also the earliest age a kitten should leave its mother, though 12 weeks is better.
How old is a 6 week old kitten in human years?
About 18 months in human terms — a toddler. At six weeks a kitten is eating solid food, playing hard, and learning most of its social behaviour from its mother and littermates. It is too young to be rehomed.
How old is a 6 month old cat in human years?
Around 10 in human years. By six months all the adult teeth are through, growth is still fast, and the cat is approaching sexual maturity — which is why most vets neuter around this age or a little earlier.
How old is an 11 month old cat in human years?
Roughly 14 and a half — a late teenager. Growth has slowed noticeably and most cats can switch from kitten food to adult food around this point. At 12 months the cat reaches the human equivalent of 15.
When does a kitten become a cat?
Officially at 12 months, which is when most vets consider a cat an adult and switch it to adult food. Behaviour takes longer: cats stay playful and adolescent until around 18 months to two years, and large breeds like Maine Coons keep filling out for far longer.
How can I tell how old a kitten is?
Teeth are the most reliable clue. Eyes open at 7–14 days, baby teeth appear from 2–4 weeks and are complete by 8 weeks, adult teeth start replacing them at 3–4 months and are all in by 6–7 months. Weight helps too: a healthy kitten gains roughly 100 g a week for the first few months.