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Kitten Age Calculator: How Old Is My Kitten?

If you've found or adopted a kitten and aren't sure how old they are, this kitten age calculator helps you estimate their age from physical milestones — teeth, eyes, ears, movement, and weight.

Updated 2026-06-05 en-US Client-side calculator

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Try the Kitten Age Calculator: How to Tell How Old a Kitten Is

Enter a few values to get a fast estimate. Results stay in your browser and can be copied, shared, or saved locally.

published low risk en-US

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Estimate how old your kitten is

Found a kitten or unsure of their age? Answer what you can see — teeth and eyes tell us the most — for a gentle age estimate and the right care for that stage.

An educational estimate from physical milestones — your veterinarian can confirm age and health.

Estimated kitten age

Answer a few clues above

We'll show an age range here.

Life stage

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Weight cross-check

Add a weight to compare

Enter what you can see to estimate your kitten's age.

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    Frequently asked questions

    How can I tell how old a kitten is?

    The most reliable clues are teeth and eyes. Newborns have closed eyes and no teeth; eyes open around 1–2 weeks; baby teeth appear from 2–6 weeks; and adult teeth come in around 3–6 months. Weight is a helpful cross-check — kittens gain about 4 oz (110 g) a week.

    How old is a kitten by teeth?

    No teeth means under about 2 weeks. Tiny front teeth (incisors) appear around 2–4 weeks, small fangs by 3–5 weeks, and most baby teeth are in by 6–8 weeks. Adult teeth replace them between about 3 and 6 months.

    How much should a kitten weigh by age?

    A rough rule is that a young kitten gains about 4 ounces (110 g) per week, reaching roughly 1 pound by 4 weeks and 2 pounds by 8 weeks. Use weight to sanity-check the milestone-based estimate.

    When can a kitten leave its mother?

    Kittens are usually ready for a new home from about 8 to 12 weeks, once weaned, litter-trained, and well socialized. Younger kittens still need their mother or careful hand-rearing.

    How this calculator works
    1. Select what you can observe — teeth and eyes are the most reliable clues to a kitten's age.
    2. The calculator combines your answers into an age range in weeks (and months for older kittens).
    3. It then shows the life stage and the specific care a kitten of that age needs.

    Input guide
    • Check the mouth gently: are there no teeth, tiny front teeth, small fangs, a full set of baby teeth, or adult teeth coming in?
    • Note the eyes (closed, just opening and blue, or fully open) and ears (folded flat or upright).
    • Add a weight if you can — a kitten gains about 4 oz (110 g) per week, which cross-checks the estimate.

    Result explanation

    The result is an age range, because milestones overlap and every kitten grows a little differently.

    Teeth and eyes carry the most weight; behavior and weight help confirm the range.

    Use the care tips for that stage, and confirm age and health with your veterinarian.

    Helpful tips
    • Very young kittens (under 4 weeks) need warmth, frequent formula feeds, and help to toilet — never cow's milk.
    • Weigh the kitten daily; steady gain is one of the best signs of good health.
    • From about 4 weeks, start gentle weaning and lots of socialization.

    Common mistakes
    • Feeding cow's milk, which upsets a kitten's stomach — use kitten formula.
    • Underestimating how often newborns must eat (every 2–3 hours).
    • Rehoming a kitten before it is weaned and socialized at 8–12 weeks.