Cat Age Calculator

Short answer: the first two years of a cat’s life come to 24 human years, and after that each cat year is worth about 4 human years — so a 1-year-old cat is about 15, a 2-year-old about 24, and a 10-year-old about 56. That is International Cat Care’s published table. Where the sources don’t agree is the senior threshold: one veterinary guideline says 10, another says 11 — and this page sets both out rather than picking one.

Cat years to human years

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    The formula, and where it comes from

    Unlike the dog version of this page, there is only one widely published cat conversion, and it comes from a single named authority — so there is no disagreement to show you here.

    International Cat Care puts it in one sentence:

    “The first two years of a cat’s life equate to 24 human years and every year thereafter is equivalent to 4 human years.”

    Which breaks down as 15 for year one, 9 more for year two, and 4 for every year after that. Their own worked example: a 16-year-old cat is about an 80-year-old human.

    Source: International Cat Care — Special considerations for senior cats, and the charity’s How old is your cat? chart (Cat Friendly Clinic handout), both read October 13, 2026. International Cat Care is a feline welfare and veterinary charity; the chart is part of its Cat Friendly Clinic programme.

    Your cat’s life stage

    Both authorities group cats by life stage, and here they do agree on the early ones. International Cat Care’s stages, from its own chart:

    StageAgeHuman equivalent at the ends
    KittenBirth – 6 months0 – about 10
    Junior7 months – 2 years12 – 24
    Adult3 – 6 years28 – 40
    Mature7 – 10 years44 – 56
    Senior11 – 14 years60 – 72
    Super senior15 years and over76 and up
     International Cat Care, “How old is your cat?” chart, read October 13, 2026. The human-equivalent columns are the ends of each stage, taken from the same chart.

    The AAHA/AAFP 2021 Feline Life Stage Guidelines use four stages — kitten (birth to 1 year), young adult (1–6), mature adult (7–10) and senior (over 10) — with end-of-life as a fifth that can occur at any age. Their wording is worth keeping in mind for any chart on this subject: “any age groupings are inevitably arbitrary demarcations along a spectrum and not absolutes.”

    When is a cat senior? Two answers

    This is the one place the sources visibly disagree, and it is a difference of a year rather than a contradiction:

    SourceMatureSenior
    AAHA / AAFP 2021 Feline Life Stage Guidelines7–10 yearsOver 10 years
    International Cat Care Cat Friendly Clinic chart7–10 years11–14 years (15+ is “super senior”)
     Both read October 13, 2026. The AVMA, in its senior pet guidance, also describes cats as “senior” after 10 years, citing the AAHA/AAFP guidelines.

    So a cat of exactly 10 or 11 is in the gray area, and which label applies depends on whose chart you are reading. That is not a problem to solve — it is a reason to treat the number as a nudge to get a check-up rather than a diagnosis.

    What both agree on is the practical consequence: the AAHA/AAFP guidelines say senior cats should be seen at least every six months, and more often with a chronic condition. The AVMA likewise recommends twice-yearly examinations for senior pets.

    Cats and dogs: the same start

    A detail that surprises people: for the first two years, cats and dogs age at almost exactly the same rate.

    AgeCat (iCatCare)Dog (AVMA, medium breed)
    1 year1515
    2 years2424
    Each year after+4+5
     International Cat Care and the AVMA (via the AKC) respectively, read October 13, 2026. Identical for the first two years, then cats slow down slightly relative to dogs.

    That is why the dog and cat versions of this calculation feel interchangeable at the start and diverge in old age: a 15-year-old cat and a 15-year-old dog are roughly 76 and 89 in human years. If you want the dog side, it is on our dog age calculator.

    The full cat age chart

    International Cat Care’s chart, reproduced with the rows between its published ages filled in by linear interpolation. The figures are theirs; the interpolation between them is ours, and nothing has been recalculated.

    Cat’s ageHuman equivalentLife stage
    0–1 months0Kitten
    2 months2Kitten
    3 months4Kitten
    4 months6Kitten
    5 months8Kitten
    6 months10Kitten
    7 months12Junior
    12 months15Junior
    18 months21Junior
    2 years24Junior
    3 years28Adult
    4 years32Adult
    5 years36Adult
    6 years40Adult
    7 years44Mature
    8 years48Mature
    9 years52Mature
    10 years56Mature
    11 years60Senior
    12 years64Senior
    13 years68Senior
    14 years72Senior
    15 years76Super senior
    16 years80Super senior
    18 years88Super senior
    20 years96Super senior
    25 years116Super senior
     From the “How old is your cat?” chart published by International Cat Care for its Cat Friendly Clinic programme, read October 13, 2026. Reproduced with the source named and linked.

    What changes in a senior cat

    The conversion is the easy part. The reason the senior threshold matters is what vets start looking for at that age — and one warning is specific to cats.

    The AVMA puts it plainly: “sudden weight loss in a senior pet often means something is wrong, especially in cats”, listing hyperthyroidism, cancer, diabetes, and kidney disease among the common causes. In dogs, the greater concern is weight gain; in cats it is the opposite. That is a useful thing to know even though it is not a conversion.

    The same source notes that cancer is the cause of death in about a third of cats over 10, and that kidney or urinary disease, heart disease, diabetes, and joint disease all become more common. None of that is something to diagnose at home, and this site does not give veterinary advice — it is a reason the six-monthly check exists.

    Source: AVMA — Caring for senior cats and dogs (senior age from the AAHA/AAFP feline guidelines; the weight-loss warning; cancer proportion; twice-yearly examinations). Read October 13, 2026.

    What to buy

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    We do not show prices. Anything to do with diet, supplements or a health condition is worth raising with your vet first — we link to products, not to advice.

    Questions we get a lot

    How do you convert cat years to human years?

    International Cat Care states that the first two years equate to 24 human years and every year after is worth 4. So 1 year is about 15, 2 years about 24, 10 years about 56, 15 years about 76.

    When is a cat considered senior?

    It depends which guideline you read. The AAHA/AAFP 2021 guidelines say senior after 10 years; International Cat Care treats 7–10 as mature and 11–14 as senior, with 15 and over as super senior.

    How often should a senior cat see a vet?

    At least every six months according to the AAHA/AAFP guidelines, and more often with a chronic condition. The AVMA also recommends twice-yearly exams for senior pets.

    Is weight loss in an older cat a concern?

    Yes — the AVMA states that sudden weight loss in a senior pet often means something is wrong, especially in cats, and lists hyperthyroidism, cancer, diabetes, and kidney disease. See your vet.

    Do cats and dogs age at the same rate?

    The first two years are almost identical — about 15 then 24 in human years for both. After that cats add roughly 4 a year and dogs about 5, so they drift apart with age.

    Can you tell me how long my cat will live?

    No. Lifespan varies far too much between individuals and breeds, and no authority publishes a reliable per-cat prediction. The age conversion tells you a life stage, not an endpoint.

    How we work this out

    What this page will not do: it will not tell you how long your cat will live, what to screen for, or what a symptom means. It converts an age and names a life stage.

    Sources: International Cat Care — How old is your cat? (Cat Friendly Clinic chart) and Special considerations for senior cats (the 24-plus-4 rule and the worked 16-year example); AAHA/AAFP 2021 Feline Life Stage Guidelines — life stage definitions (four stages plus end-of-life; “arbitrary demarcations”; six-monthly senior examinations); AVMA — Caring for senior cats and dogs (senior after 10; weight-loss warning in cats; cancer proportion). All read October 13, 2026.

    Last updated: 2026-10-19.