Brown tabby cat resting on a windowsill in warm daylight
Photo: Chris Barbalis / Unsplash
Updated for 2026 · AAFP/AAHA Feline Life Stage formula

How old is your cat,
really?

Reviewed by Carl Updated Method

Personalised, breed-aware, and — uniquely for cats — adjusted for the single biggest lifespan variable: indoor versus outdoor access. Get an honest answer in about ten seconds.

Formula Year 1 = 15 · Year 2 = +9 · Year 3+ = +4 per year

AAFP/AAHA feline life-stage formula. Lifestyle (indoor/mixed/outdoor) adjusts expected lifespan, not the year-to-year math.

Full method →
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Save a cat for one-click recall After your first calculation, click Save cat in the result. Saved cats appear here on every visit — across all your browser tabs.

Cat age calculator

Personalised, breed-aware, and lifestyle-adjusted. Indoor-only cats live more than twice as long as outdoor cats — we factor that in.

  • Abyssinian short-hair
  • American Curl short-hair
  • American Shorthair short-hair
  • American Wirehair short-hair
  • Bengal short-hair
  • Birman long-hair
  • British Shorthair short-hair
  • Burmese short-hair
  • Burmese short-hair
  • Chartreux short-hair
  • Cornish Rex short-hair
  • Cymric long-hair
  • Devon Rex short-hair
  • Domestic Longhair long-hair
  • Domestic Shorthair short-hair
  • Egyptian Mau short-hair
  • European Shorthair short-hair
  • Exotic Shorthair short-hair
  • Havana Brown short-hair
  • Japanese Bobtail short-hair
  • Khao Manee short-hair
  • Korat short-hair
  • LaPerm medium-hair
  • Lykoi short-hair
  • Maine Coon long-hair
  • Manx short-hair
  • Manx short-hair
  • Munchkin short-hair
  • Nebelung long-hair
  • Norwegian Forest Cat long-hair
  • Ocicat short-hair
  • Oriental Shorthair short-hair
  • Persian long-hair
  • Pixie-Bob short-hair
  • Ragdoll long-hair
  • Russian Blue short-hair
  • Savannah short-hair
  • Scottish Fold short-hair
  • Selkirk Rex long-hair
  • Siamese short-hair
  • Singapura short-hair
  • Snowshoe short-hair
  • Sphynx hairless
  • Tonkinese short-hair
  • Tonkinese short-hair
  • Toybob short-hair
  • Toyger short-hair
  • Turkish Angora medium-hair

Start typing to filter. Most household cats are best estimated with the "Mixed / unknown" tab.

Your cat
0 human years

That's about the same as a human young adult.

Expected remaining lifespan
— years

Indoor cats live nearly 3× as long as outdoor cats on average.

Done

The cat formula in one paragraph

Cats age fast in their first two years and slowly after. The first year of life is roughly equivalent to 15 human years. The second year adds 9 more — so a two-year-old cat is about 24 human years old, already a young adult. From year three onward, each cat year adds about 4 human years. That means a 10-year-old cat is approximately 56 in human years, and a 20-year-old cat is approximately 96.

Why lifestyle matters more than breed

For dogs, body size is the dominant lifespan variable. For cats, it's lifestyle. Multiple veterinary studies converge on the same picture: indoor-only cats live a median of 12–18 years, while outdoor-only cats live a median of 3–7 years. Indoor + outdoor cats land in the middle, around 11 years. The gap is driven by trauma, infectious disease, predators, and toxic exposures — risks that disappear when cats stay inside.

If you take away one thing. The single most impactful change you can make for a cat's expected lifespan is keeping them indoors (or providing a secure outdoor enclosure / leash-walking instead of free roam).

Cat life stages (AAFP / AAHA 2021)

The American Association of Feline Practitioners defines six practical life stages, which the calculator surfaces alongside the human-age result:

  • Kitten (0–6 months): rapid growth, vaccinations, socialisation.
  • Junior (7 months – 2 years): sexually mature, personality still forming.
  • Adult (3–6 years): prime years, weight and dental focus.
  • Mature (7–10 years): subtle aging signs, baseline bloodwork.
  • Senior (11–14 years): twice-yearly vet visits, kidney/thyroid monitoring.
  • Geriatric / super-senior (15+ years): comfort-focused care.

How accurate is the cat formula compared to the dog formula?

More accurate, actually. Cats vary much less in size than dogs do — even a large Maine Coon and a small Singapura age along essentially the same curve. The formula's main weakness is the long tail: cats can live to 20+ in good health, and the formula assumes a steady ~4 human years per cat year that doesn't account for the slowdown that some long-lived cats experience past 18.

How to use this calculator

  1. Pick your input mode: by breed (for purebreds and breed-specific lifespan notes) or mixed / unknown (for typical household cats).
  2. Optionally enter your cat's name — the result will be personalised.
  3. Pick the lifestyle: indoor, indoor + outdoor, or outdoor.
  4. Enter your cat's age in years (and months for kittens).
  5. Click "Calculate human age". Results include the human-equivalent age, current life stage, and expected remaining lifespan based on your cat's lifestyle.

Sources: AAFP / AAHA Feline Life Stage Guidelines (2010, refreshed 2021). International Cat Care lifestyle / lifespan position statements. Mar Vista Animal Medical Center summary. WSAVA Global Nutrition Guidelines for life-stage nutrition.

Daily calorie needs (cats)How many kcal per day, with a safer feline weight-loss plan.
Lifetime cost of ownershipWhat 15 years with a cat actually costs — food, vet, litter, the lot.
Compare your dog and catSee which of your pets is "older" in human-equivalent years.

Frequently asked questions

How old is my cat in human years?

Using the AAFP/AAHA Feline Life Stage formula, the first year of a cat's life equals about 15 human years, the second adds 9 more (total ~24 at age 2), and each year after adds 4. So a 7-year-old cat is approximately 44 in human years, and a 15-year-old cat is approximately 76. Try the calculator above with your cat's exact age and lifestyle for a precise answer.

Why are indoor cats expected to live so much longer than outdoor cats?

Outdoor cats face dramatically higher risks: trauma (vehicles, dogs, other cats), infectious disease (FIV, FeLV, parasites), predators, poisoning, and exposure. Studies consistently show indoor-only cats live 12–18 years on average while outdoor-only cats live 3–7 years on average. Indoor + outdoor "mixed" cats fall in between.

When is a cat considered a senior?

AAFP defines senior status starting at 11 years. Mature stage (7–10 years) is when subtle age-related changes typically begin. Geriatric (super-senior) stage starts at 15 years. Senior cats benefit from twice-yearly veterinary visits with regular bloodwork.

Does breed affect cat aging?

Much less than for dogs. The main breed-related variables are lifespan averages (Siamese, Burmese, and Russian Blues tend to be long-lived; some giant breeds like Maine Coons run slightly shorter) and breed-specific health predispositions. Choose a breed page from the calculator for breed-specific notes.

Does the cat formula work for kittens?

Yes. A 3-month-old kitten is approximately 5–6 human-equivalent months in maturity. The first-year multiplier covers rapid kitten development. By 6 months, a kitten is roughly equivalent to a 10-year-old human; by 1 year, ~15.

My cat lives partly indoors and partly outdoors. Which lifestyle do I pick?

Use "Indoor + outdoor". The median lifespan estimate of ~11 years reflects real outcomes for mixed-access cats — significantly shorter than indoor-only but longer than outdoor-only.

Should I use this calculator instead of asking my vet?

No. This is a free educational tool. Your veterinarian can assess body condition, dental health, mobility, and clinical signs that no calculator can see. Use the result as a conversation starter at your next visit.

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