Kitten Age Chart: How Old Is This Kitten, and What Does It Need Right Now?

Whether you have just found a kitten in a hedge or brought one home, the two questions are the same: how old is it, and what does that age need? Kittens change almost by the day, on a schedule reliable enough that rescuers age them by teeth and eyes rather than paperwork. The chart below compresses that schedule, built on the weekly benchmarks published by Alley Cat Allies, the US rescue organization whose age guide is the field standard; the care notes that follow come from the veterinary and shelter literature, with each source named.

One line before the chart, because it can save a life: a kitten under about 3 weeks cannot hold its own body temperature and cannot be fed cow's milk. If you have found one that young, warmth first, then a vet or rescue for kitten formula, and our stage sections below cover the rest.

The chart

Two reading tips. The teeth are the most reliable clock in a found kitten: no teeth means under 2 weeks, incisors only points to 2 to 3, canines from 3 to 4, premolars from 5, the full 26 by 8. And all kittens have blue eyes until the adult color starts to emerge around 7 weeks, so blue eyes alone prove nothing about breed and only a little about age.

Newborn to 2 weeks: warmth is the whole job

A newborn kitten sleeps about 90% of the time and eats the rest. That is the extreme end of a lifelong career: why cats sleep so much explains how the hours change from kitten to senior. It cannot see, barely hears, cannot pass waste without its mother's stimulation, and, critically, cannot regulate its own body temperature: chilling is the classic killer of orphaned neonates, which is why every rescue protocol puts a heat source before food. Kittens need supplemental warmth until about 3 to 4 weeks, per the Best Friends Animal Society bottle-feeding guide, and a chilled kitten must be warmed before it is fed.

Orphans this age are fed kitten formula from a bottle, every two hours around the clock in the first days, stretching to every three to four hours after about day ten. Never cow's milk, at any age, and the reason is worth stating precisely: nursing kittens digest milk perfectly well, because their gut produces lactase for exactly that job. The enzyme declines as weaning approaches, and cow's milk carries more lactose than the fading supply can process, so it ferments in the gut and causes diarrhea, which in a tiny kitten is genuinely dangerous. Kitten formula exists because the milk itself must be cat-shaped, not because milk is poison. Why adult cats and cow's milk disagree is its own story.

Weight is the health dashboard. Laid end to end, the chart's own weekly figures work out to roughly 10 to 15 grams of gain a day in the early weeks. A kitten that stops gaining for a day or two, or loses weight, is telling you something is wrong: that is a call to a vet or rescue, not a wait-and-see.

Everything before day one is on our guide to how long cats are pregnant; the delivery itself, stage by stage, and the signs that mean a vet call are on cat giving birth, and the nine weeks before that first weigh-in are on the cat pregnancy stages timeline. Litters average about four kittens, and the first week is when most early losses happen; the measured figures are on how many kittens a cat can have.

2 to 4 weeks: the world switches on

Eyes fully open at 2 weeks, ears up by 3, first wobbly steps in between. Two care milestones land here:

• The litter box arrives at 3 weeks, when kittens first become able to eliminate on their own; Alley Cat Allies' protocol is a small, shallow box with non-clumping litter, and by 6 weeks kittens should be using it reliably. (That window rests on the one organization's published guide, and it matches the physiology.)
• Deworming starts at 2 weeks, per the Companion Animal Parasite Council's guideline: every two weeks until 2 months old, then monthly until 6 months. Kittens pick up roundworms through their mother's milk, which is why the schedule starts before most owners would think to. Our cat worms guide explains what they are up against.

This is also when the most important invisible clock starts. The veterinary life-stage guidelines put it precisely: the sensitive socialization window for new experiences, people and other animals opens as early as 2 to 3 weeks and may be closing by 9 to 10 weeks, a fluid period where the quality of experiences matters most, with a recommended dose of 30 to 60 minutes of pleasant human interaction a day. A kitten gently handled through these weeks becomes a confident cat; one that meets no humans before the window closes may never fully trust them.

4 to 6 weeks: weaning, a window rather than a day

Around 4 weeks, kittens start on solid food: the standard method is a gruel of kitten formula mixed with wet food, gradually shifted toward plain wet food over a week or two, with water available from the first solid meal. By 5 weeks they are mostly eating solids in 4 or 5 small meals a day; by 6 weeks they should be weaned, though they may still comfort-nurse if their mother is around, and that is normal. Thermoregulation is substantially online by 4 weeks, so the heat source can retire.

Do not rush this. The weaning age is one of the best-studied numbers in cat behavior, and it points the other way: in a University of Helsinki study of 5,726 cats, weaning before 8 weeks increased the risk of aggression, and cats weaned at 14 weeks or later had fewer behavior problems than those weaned at 12. Separating early costs temperament. The full where-and-when, including what the law says in each of our four markets, lives in our guide to when kittens can leave their mother.

6 to 8 weeks: vaccines, and the two-pound milestone

The first core vaccination lands at 6 to 8 weeks, protecting against panleukopenia and the two respiratory viruses, with boosters every 2 to 4 weeks until 16 to 18 weeks; the reason for all those boosters is maternal antibodies, which protect the kitten and neutralize vaccines unpredictably for weeks. Our cat vaccinations guide covers the full schedule, the laws and the costs.

By 8 weeks a healthy kitten weighs about 2 pounds, carries all 26 baby teeth, and is done with bottles for good. Two pounds is also the weight at which rescue organizations spay and neuter, which is why shelter kittens typically go home altered at 8 weeks and up.

8 to 12 weeks: ready, then readier

From 9 weeks the adult eye color is in, the full adult body language repertoire is running, and a well-socialized kitten actively seeks laps and attention. Social play with littermates keeps climbing to a peak around 12 weeks, which is one more thing a kitten gets from staying with its family a little longer. Shelters commonly adopt out from 8 weeks; pedigree registries recommend longer, and the UK's GCCF says 13 weeks with vaccinations completed. That debate, with the evidence and the law market by market, is the satellite guide's whole subject.

Feeding from here: kitten food, not adult food, in several small meals; the portion mathematics of adulthood, covered in our how much to feed a cat guide, takes over around the first birthday. What the adult weight should settle at depends on build, and the adult weight chart has the measured figures. And since the first year is when the expensive surprises concentrate, from swallowed string to the diseases that pick on the young, this is also the age band where kitten insurance decisions are usually made.

One line for anyone keeping a female kitten: some cats come into their first heat as early as 4 months, so the spay conversation belongs before then (see cat in heat). The date to put in the diary is the spay or neuter, by five months in the US and Canada and around four in the UK and Australia: why the age moved in 2016. If she reaches her first heat before the appointment, she can still be spayed.

What to take away

• Teeth are the most reliable kitten age clock: none under 2 weeks, incisors at 2 to 3 weeks, canines from 3 to 4, premolars from 5, all 26 baby teeth by 8 weeks.
• A healthy kitten weighs about 2 lb (roughly 900 g) at 8 weeks and gains roughly 10 to 15 g a day in the early weeks; a stall or a loss is a call to the vet.
• Kittens cannot hold their own body temperature until 3 to 4 weeks: for a found kitten, warmth comes before food.
• Kitten formula, never cow's milk: lactase declines as weaning approaches, and cow's milk causes diarrhea that is genuinely dangerous at this size.
• Deworming starts at 2 weeks (every two weeks to 2 months, then monthly to 6 months, per CAPC); the first core vaccines land at 6 to 8 weeks.
• The socialization window opens at 2 to 3 weeks and may close by 9 to 10: gentle daily handling inside that window shapes the adult cat, and the window does not reopen.