How to Tell How Old a Kitten Is

You can date a kitten to within a few days in the first month, and the fastest way is to look at its face rather than weigh it. Eyes and ears change on a tight schedule that varies little between kittens, and teeth take over as the reliable marker once the eyes are open — while weight is the least trustworthy single clue, because a starved kitten can be half the weight of a well-fed one the same age. Use several signs together and you will get close. The estimate matters practically: it decides whether a kitten needs bottle feeding or a bowl, when worming starts, and when vaccines are due. Cross-check your figure with the kitten weight calculator.

The Quick Version

If you are standing in a garden holding a kitten, work through these in order.

Is the umbilical stump still attached? Under about three days old. The cord dries and falls off within the first few days.

Are the eyes shut? Under seven to ten days. They open between roughly day seven and day fourteen, often one eye before the other.

Are the ears still flat against the head? Under about two weeks. They unfold from around two weeks and stand upright by three.

Can it walk properly, or does it wobble and drag? Wobbling means around three weeks; walking confidently means about four.

Are there teeth? Run a clean finger along the front gum. Sharp little incisors mean two to three weeks; canines mean three to four; back teeth mean four weeks or more.

Are the eyes still that flat kitten-blue? Blue until about six to seven weeks. Green, gold or copper appearing means seven weeks or older.

Then check the weight against your estimate, using it as a cross-check rather than as the answer.

The Ageing Table

The signs together, with the age each one points to.

Ranges overlap deliberately. Individual kittens vary, and a table that gave single figures would be lying to you.

Where two signs disagree, trust the teeth and eyes over the weight. Development happens on a schedule; growth depends on nutrition.

The fuller weight ranges are in kitten weight by age chart if you want more granularity for the older ages.

Eyes: The First Two Weeks

The most reliable marker in the newborn period, because the timing is tight.

Kittens are born with the eyelids fused shut and stay that way for about seven to fourteen days, with most opening around day ten.

They often open one eye first, sometimes a day or two ahead of the other, which looks alarming and is normal.

Vision is poor at first. For the first few days after opening, the eye looks hazy and blue-gray and the kitten is not tracking properly. Focused, tracking vision arrives around three to four weeks.

Every kitten's eyes are blue at first. The iris has not yet developed its adult pigment. Adult color starts to show through from about six to seven weeks and is usually settled by three months.

Blue eyes therefore date a kitten to under about seven weeks, and a definite green or copper eye means seven weeks or more — with the exception of breeds and cats that keep blue eyes for life, such as Siamese and many white cats.

A swollen, bulging or discharging closed eyelid is not a stage. That is an infection behind the lid and needs a vet the same day. The normal course is set out in when do kittens open their eyes.

Ears and Hearing

Less precise than eyes, but useful for the second and third weeks.

Newborn ear flaps are folded flat and closed, sitting low against the side of the head, and the ear canals are sealed.

Unfolding starts around two weeks and the ears look small, rounded and slightly crumpled as they lift.

By three weeks they stand upright and start to swivel towards sounds.

Hearing arrives with the canals opening, at roughly two to three weeks. A kitten that startles at a clap is at least two weeks old; one that ignores it entirely is probably younger.

Ear shape keeps changing until about four to five weeks, when they take their adult proportions relative to the head — one reason a five-week kitten looks all ears.

Check inside while you are looking. Dark, crumbly, coffee-ground debris in a kitten's ears is ear mites, extremely common in found kittens and easily treated, but not something to attempt with adult products.

Teeth: The Most Precise Clue After Two Weeks

Once the eyes are open, teeth do the dating, and the sequence is consistent.

Deciduous incisors erupt first, from about two to three weeks — the tiny row of pinpricks at the front.

Canines follow at roughly three to four weeks, the four longer needle teeth. These are what make a four-week kitten's bite feel disproportionately sharp.

Premolars come in from about four to six weeks, working backwards along the jaw.

All 26 deciduous teeth are usually present by six to eight weeks. Kittens have no deciduous molars, which is why the milk set is 26 rather than 30.

No teeth are lost until around three months. So a kitten with a complete, clean milk set and no gaps is somewhere between about eight weeks and three months — a wide window, which is why teeth become less precise after weaning.

Then the replacement sequence dates older kittens, from about three months to six or seven, and it is set out in when do kittens lose their baby teeth. Gappy incisors mean roughly three to four months; adult canines coming through alongside milk ones means about four to six.

Movement and Behavior

Coarser than teeth, but you can assess it from across a room.

Under two weeks, a kitten cannot stand. It crawls with a swimming motion, dragging the belly, and the head sways.

Around two weeks it pushes up on its front legs and starts trying to bear weight behind.

First wobbly steps come at roughly two and a half to three weeks, with a wide, rocking gait and frequent tipping over.

Confident walking is about four weeks. Running, pouncing and climbing arrive around five to six, along with proper play with littermates.

Grooming itself is a four-week behavior, and by six weeks a kitten washes reasonably competently.

Self-toileting starts around three to four weeks. A kitten that still needs stimulating to urinate is under about four weeks, which is one of the most decision-relevant facts on this page. The timeline is in when do kittens start walking.

Weight as a Cross-Check, Not an Answer

Useful, but the sign most likely to mislead you.

Roughly 100 g per week — about 3.5 oz — is the rule of thumb in the first two months, starting from about 100 g at birth. The shortcut only works in grams, so keep the scale switched to them for this one: a kitten's age in weeks is close to its weight in grams divided by 100.

Which gives you a quick estimate: 250 g (about 9 oz) is around two to three weeks, 500 g (a bit over 1 lb) around four to five, 1 kg (2.2 lb) around eight to ten.

But a starved or sick kitten breaks the rule badly. A found kitten that has been without a mother can weigh what a kitten half its age weighs, and dating it by weight alone will land you feeding it the wrong thing.

Breed changes it too. A Maine Coon kitten runs ahead of the table and a small-breed or runt kitten behind it.

So use weight to confirm, not to decide. If teeth say five weeks and weight says three, the kitten is five weeks old and underweight — which is itself the most important finding.

Record the weight daily from the day you find it. The gain trend tells you more about the kitten's condition than the absolute number does, and the expected daily figures are in kitten weight by age chart.

Why the Age Estimate Actually Matters

Four practical decisions hang on it.

Whether it drinks or eats. Under about three and a half weeks a kitten needs kitten milk replacer every two to three hours; from four weeks it can start gruel; by seven to eight it should be on solid kitten food. Getting this wrong in either direction causes harm — see when can kittens eat solid food.

Whether it needs toileting help. Under three to four weeks, a kitten cannot urinate or defecate without stimulation, and a kitten wrongly aged as older will simply stop passing urine.

When worming starts. Most protocols begin at two to three weeks and repeat fortnightly, so an age estimate sets the whole schedule.

When vaccines are due. The first vaccination is usually given at around eight to nine weeks with a second three to four weeks later, and giving it too early wastes it against maternal antibodies. The detail is in kitten vaccination schedule.

It also sets the adoption date. Eight weeks is the absolute minimum for rehoming and twelve is better, so an accurate age protects a kitten from being placed too early.

And it changes the urgency of everything. A three-week-old found alone is a genuine emergency; an eight-week-old found alone is a rescue. The hand-rearing routine is in how to care for orphaned kittens.

Getting a Vet or Rescue to Confirm It

Your estimate is a working figure, not a verdict.

Say it as a range. "About four to five weeks" is an honest and useful thing to tell a vet; "four weeks and two days" is not.

A vet will refine it using dentition, body condition, muscle development and the state of the growth plates on radiographs if there is a genuine reason to know precisely.

Growth plates close between about eight and eighteen months, which is how an older kitten or young adult is aged when the teeth have finished changing.

Rescues age kittens constantly and are often better at the two-to-eight-week range than a general practice, because they see hundreds. If you have found a litter, ring one.

Ageing a found kitten is never precise, and nothing goes wrong if you are a few days out. What matters is landing in the right bracket — under four weeks or over it, under eight weeks or over it — because those are the boundaries that change what you do.

When in doubt, treat a kitten as younger than you think. Stimulating a five-week-old that no longer needs it does no harm, whereas failing to stimulate a three-week-old does.

Frequently Asked Questions

What is the fastest way to tell how old a kitten is?

Look at the eyes and ears first. Closed eyes mean under seven to ten days, opening eyes mean one to two weeks, and upright ears mean about three weeks. Then check for teeth, which date kittens reliably from two to eight weeks.

Can I tell a kitten's age by weight alone?

Not reliably. Roughly 100 g (3.5 oz) per week is a useful rule, so 500 g — a bit over a pound — is about five weeks, but a starved kitten can weigh half what a well-fed one of the same age does. Use weight to cross-check teeth and eyes, never on its own.

At what age do kittens' eyes change color?

Adult eye color starts appearing from about six to seven weeks and is usually settled by three months. All kittens begin with blue eyes, so a definite green or copper eye means the kitten is at least seven weeks old.

How old is a kitten when its teeth come in?

Incisors erupt at two to three weeks, canines at three to four, and premolars from four to six. The full set of 26 milk teeth is normally in by six to eight weeks, with nothing lost again until about three months.

How can I tell if a kitten is under four weeks old?

Wobbly or absent walking, blue hazy eyes, few or no back teeth, and needing stimulation to urinate all point to under four weeks. That threshold matters because such a kitten needs milk replacer and toileting help rather than a bowl.

Does a vet need to confirm a kitten's age?

For most purposes an estimated range is enough, but a vet visit is worth it for a found kitten anyway. They will refine the age from dentition and body condition and set the worming and vaccination schedule from it.

Ageing a kitten works best as a stack of clues rather than a single measurement: umbilical stump under three days, closed eyes under ten, unfolding ears at two weeks, wobbly steps at three, canines at three to four, premolars at four to six, and blue eyes giving way to adult color at six or seven weeks. Weight confirms the picture but never sets it, because condition distorts it badly. Aim for the right bracket rather than the right day, and if two signs disagree, assume the younger age and treat accordingly. Sanity-check the numbers with the free kitten weight calculator.