🔎 Kitten Age Estimator
Found a kitten, taken in a foster, or adopted one with no birthday? Age decides everything in the first weeks — feeding rhythm, warmth, weaning — so let's work it out from what you can actually see: eyes, ears, teeth, movement and appetite. Answer what you can, skip the rest; the estimate sharpens as you go.
What can you see?
Every answer is optional — one good clue beats none. If you can safely peek at just one thing, make it the teeth: they're the single most reliable age sign. Never force a mouth open; a quick look while they yawn or mew is enough.
All kittens are born with blue eyes; the adult colour starts creeping in from about 6 weeks.
The cord usually falls off around day 3–5 — a strong clue in the very first week, useless after it.
Kitchen scales + a mixing bowl work fine. Weight backs up the physical signs — it never overrules them, because breed, sex and how well a kitten has been fed move it a lot.
Estimated age
Answer at least one clue on the left and the estimate appears here — even a single sign helps. Teeth are the most useful if you can peek safely.
How the clues voted
This is a developmental estimate, not a confirmed age — only a veterinarian who examines your kitten can age them reliably. If you just found this kitten, a vet or rescue call today beats any calculator, this one included.
Found this kitten? Your first 24 hours
Boy or girl? The under-tail check
While you're ageing a found kitten, you'll probably wonder. Look at the two openings under the tail: on a female they sit close together, like an upside-down exclamation mark (¡); on a male there's a clear gap — where the testicles will develop — and the rear opening is round, more like a colon (:). It's easiest to judge from about 3–4 weeks, comparing littermates side by side makes it obvious, and even professionals get it wrong at two weeks — your vet will confirm at the first visit.
Why estimate the age at all?
Age is the care instruction
In the first eight weeks, feeding rhythm, warmth, weaning, litter training and first vet timing all key off age. Guess two weeks wrong in either direction and the care is wrong too — a 2-week-old offered solid food, or a 6-week-old still treated like a newborn, is a kitten whose needs are being missed.
It shows its working
Every clue's age window is published in the table below, disagreements between clues are named out loud, and the answer is always a range — never a fake-precise "your kitten is 23 days old." That's how a vet tech reasons, and it's the honest way to reason here.
Built for the found-kitten moment
The urgent-signs warning comes first, the estimate comes with a first-24-hours checklist, and the result hands you straight to the socialization tracker and growth predictor. One page takes you from "I found a kitten?!" to a plan.
How the estimate works — every clue's window
Each answer maps to an age window in days, drawn from ASPCA kitten development material, Alley Cat Allies' kitten progression and Merck Veterinary Manual dental timings. The estimator overlaps all your clues' windows; weight (ASPCA newborn–8-week bands) is a supporting clue that can back up a result or break a tie, but never outvote a physical sign.
| Clue | What you see | Age window |
|---|---|---|
| Teeth | None · front teeth only · + baby fangs · back teeth · full baby set · adult teeth | Up to ~4 wks · 2–5 wks · 3–6 wks · 4–8 wks · from 5 wks · 3½–7 months |
| Eyes | Closed · opening · open & blue · changing colour | First 2 wks · days 7–16 · 2–7 wks · from ~4 wks |
| Ears | Folded · unfolding · upright | First 2 wks · 1–3 wks · from ~2 wks |
| Movement | Crawls · wobbly steps · walks & plays · runs & pounces | First ~2½ wks · 2–4 wks · 3–7 wks · from ~4 wks |
| Eating | Milk only · trying soft food · eats solids well | Up to ~5 wks · 3–6 wks · from ~5 wks |
| Cord | Still attached (falls off ~day 3–5) | First week |
| Weight | ASPCA bands: week 1 ≈ 70–190 g … week 8 ≈ 443–925 g | Supporting clue only |
If your clues don't overlap, the estimator reports the window the most clues agree on and names the ones that disagree — with teeth trusted first, because tooth eruption keeps the most consistent schedule.
Questions people ask
How accurate is this estimate?
With three or more agreeing clues, usually within about a week in the first two months — developmental milestones keep a fairly tight schedule. It gets looser as kittens get older (which is why adult teeth give a months-wide window) and with runts or kittens who've been underfed, whose bodies can lag their teeth. Treat the answer as a well-reasoned range for planning care, and let a hands-on vet exam refine it.
My clues disagreed. Which sign should I trust?
Teeth first — eruption timing (baby incisors around 2–4 weeks, premolars around 5–6 weeks, per the Merck Veterinary Manual) varies least between kittens. Then eyes, then movement. Weight comes last: a well-fed 4-week-old and a skinny 6-week-old can weigh exactly the same. When the estimator names a disagreement, it has already followed that order.
Can't I just go by weight?
Weight alone is the weakest clue here, which is why this tool demotes it to tiebreaker. Breed, sex, litter size and how recently — and how well — a kitten has eaten all swing it. The ASPCA bands (roughly 70–190 g at one week up to 443–925 g at eight weeks) are wide for a reason. Use weight to confirm what the eyes and teeth say, not instead of them.
Is this the same as the Kitten Growth Predictor?
No — they chain together. The Growth Predictor needs a known age to project adult size; this estimator finds the age when it's unknown. Estimate first, then take the age next door and see how big this kitten is going to get.
When does a found kitten need a vet right now, not soon?
Right now: feels cold, limp or floppy, won't feed, visibly very thin, struggling to breathe, or crying constantly. Otherwise, "today" is the right speed for a first call — young kittens change fast, and a vet or rescue can confirm the age estimate, check hydration and set you up with the right feeding plan.
Keep exploring
Kitten Socialization Tracker — the week-by-week plan for the 2–7 week window · Kitten Growth Predictor — adult size from today's age & weight · Caring for Newborn Kittens — the first 8 weeks, in depth · Bottle-Feeding Orphaned Kittens — the complete guide · Kitten Milestones — eyes, walking, weaning · All KittyButts tools
This estimator gives a developmental age estimate for planning care — it is not a diagnosis, a health assessment, or a confirmed age; only a veterinarian who examines your kitten can age them reliably. Feeding and care notes are general published foster guidance (ASPCA / Alley Cat Allies / Cornell orphaned-kitten guidance) — follow your own vet's or rescue's advice for your kitten, and seek a vet promptly for any kitten who is cold, limp, not feeding, losing weight, or struggling to breathe.