Cat Age Calculator
Cat years converted to human years.
Reviewed by the Calculation Machine team · Updated 24 October 2026 · How we check our maths
Your values
ⓘ Live results
- Human-equivalent age
- 44 years
- Life stage
- Mature
- Typical life expectancy
- 15 years
- Estimated years remaining
- 8 years
- Vet check frequency
- Annually
Quick answer
A cat's first year equals about 15 human years, its second year adds about 9, and each year after that adds about 4. So human age = 24 + (cat age − 2) × 4 for cats over two. A 7-year-old cat is roughly 44 in human years, and a 14-year-old cat is about 72.
What the Cat Age calculator does
This calculator converts your cat's age into an approximate human-equivalent age, names its life stage, and gives a rough life expectancy and years remaining for an indoor or indoor–outdoor cat. It also suggests how often a cat of that age is usually seen by a vet.
The conversion follows the feline age chart used in veterinary life-stage guidelines: cats race through childhood and adolescence in their first two years, then age at a steadier pace. That is why the old "multiply by seven" rule is wrong in both directions, too young for a 1-year-old cat and too old for a 15-year-old.
Treat the human-age figure as a way to understand behavior and health risks, not as a medical measure. Breed, weight, dental health and chronic conditions all change how a cat ages. The life expectancy figure is an average: plenty of cats live well past it. For feeding by age and weight, the cat calorie calculator is the natural next step, and the dog age calculator does the same job for dogs.
The formula
Age ≤ 1: human = age × 15 1 < age ≤ 2: human = 15 + (age − 1) × 9 Age > 2: human = 24 + (age − 2) × 4
| Symbol | Meaning | Unit |
|---|---|---|
| age | Cat's age; decimals are allowed (1.5 = 18 months) | years |
| 15, 9, 4 | Human years added in year one, year two and each later year | human years per cat year |
The 15 / 9 / 4 pattern matches the human-age equivalents in the AAFP and AAHA Feline Life Stage Guidelines and the cat age charts used by International Cat Care. The life stages shown (kitten, young adult, adult, mature, senior, geriatric) follow the six-stage scheme in the earlier AAFP/AAHA guidelines; the 2021 update groups cats more simply as kitten (to 1 year), young adult (1–6), mature adult (7–10) and senior (10+). The first year is treated as a straight line here, so a kitten under a year comes out a little younger than the charts, which put a 6-month-old at about 10 human years.
Worked examples
First birthday
An indoor cat that has just turned one.
Inputs
- Cat's age1 years
- LifestyleIndoor
Result
- Human-equivalent age15 years
- Life stageYoung adult
- Typical life expectancy15 years
- Estimated years remaining14 years
- Vet check frequencyAnnually
At 1 year a cat is about 15 in human terms: physically grown and sexually mature, but still playful and energetic. This is when most cats move from kitten food to adult food.
Middle-aged indoor cat
A 7-year-old indoor cat at the calculator's default settings.
Inputs
- Cat's age7 years
- LifestyleIndoor
Result
- Human-equivalent age44 years
- Life stageMature
- Typical life expectancy15 years
- Estimated years remaining8 years
- Vet check frequencyAnnually
Seven cat years is about 44 human years, the start of the mature stage. Weight gain and dental disease become more common from here, so keep up annual check-ups and watch portion sizes.
Senior cat with outdoor access
A 14-year-old cat that goes outdoors.
Inputs
- Cat's age14 years
- LifestyleIndoor–outdoor
Result
- Human-equivalent age72 years
- Life stageSenior
- Typical life expectancy11 years
- Estimated years remaining0 years
- Vet check frequencyEvery 6 months
At about 72 human years this cat is already past the average for indoor–outdoor cats, so years remaining shows zero. That is an average, not a forecast; check-ups every six months help catch kidney, thyroid and blood-pressure problems early.
Cat years to human years chart
Values from age 1 upward follow the formula above. Kitten months are from the veterinary age charts, which show kittens maturing even faster than a straight line suggests.
| Cat age | Human age | Life stage |
|---|---|---|
| 6 months | About 10 | Kitten |
| 1 year | 15 | Young adult |
| 2 years | 24 | Young adult |
| 5 years | 36 | Adult |
| 7 years | 44 | Mature |
| 10 years | 56 | Mature |
| 12 years | 64 | Senior |
| 15 years | 76 | Geriatric |
| 18 years | 88 | Geriatric |
| 20 years | 96 | Geriatric |
What changes at each life stage
- Kitten (to 1 year): rapid growth, vaccinations, neutering, and much higher calorie needs per kilogram than an adult.
- Young adult and adult (1–6 years): peak fitness. Weight control and dental care set up later health.
- Mature (7–10 years): activity drops and weight gain is common. Many vets start routine blood tests around now.
- Senior and geriatric (11+ years): higher risk of kidney disease, hyperthyroidism, high blood pressure, arthritis and dental disease. Twice-yearly check-ups, low-sided litter trays and lower perches help; the cat tree size calculator can help you pick a tree an older cat can still climb.
Signs worth a vet visit at any age include drinking or urinating more, weight loss despite a good appetite, hiding, and changes in grooming or litter habits.
Why indoor and outdoor cats differ
Cats with outdoor access face road traffic, fights, infectious disease such as FIV and FeLV, and predators, which pulls their average lifespan down. The calculator uses 15 years for indoor cats and 11 for indoor–outdoor cats as rough averages. Indoor cats in their late teens are common, and some reach 20. Indoor cats, in turn, are more prone to weight gain, so their portions need closer watching.
How to use the Cat Age Calculator
- 1Enter your cat's age in years; use decimals for months (6 months = 0.5, 18 months = 1.5).
- 2If you adopted an adult cat of unknown age, use your vet's estimate from teeth, eyes and coat.
- 3Choose Indoor or Indoor–outdoor to set the life-expectancy average.
- 4Read the human-equivalent age, life stage and suggested check-up frequency.
Frequently asked questions
How old is my cat in human years?
Count 15 for the first year, 9 for the second and 4 for each year after. A 3-year-old cat is about 28, a 10-year-old about 56 and a 16-year-old about 80.
Is one cat year equal to seven human years?
No. The seven-year rule makes a 1-year-old cat seem like a 7-year-old child, when it is closer to a 15-year-old teenager. After age two, cats age about 4 human years per year.
At what age is a cat considered senior?
Most vets treat cats as senior from about 10 or 11 years, roughly 56–60 in human terms. Cats over 15 are often called geriatric.
How long do indoor cats live?
Indoor cats commonly live into their mid-teens, and many reach their late teens. Cats with outdoor access live shorter lives on average, mainly because of traffic, fights and infectious disease.
How can I tell how old a cat is?
A vet estimates age from teeth (tartar and wear), eye clarity, coat and muscle tone. In adult cats the estimate is usually a range of a few years.
References
- AAHA/AAFP Feline Life Stage Guidelines — American Animal Hospital Association and American Association of Feline Practitioners
- Cat life stages guidance — International Cat Care
About this calculator
- Built and reviewed by the Calculation Machine team · How we build and test calculators
- Last reviewed: October 24, 2026
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