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CalculatorLab

Cat Age Calculator

Enter your cat’s age to see the human-year equivalent and life stage. A year is not seven years for cats either.

Your cat in human years

40

Life stage
Young adult
Cat’s age
6 y 0 m
First year15 human years
Second year+9 (24 in total)
Every year after+4

A cat’s real pace of ageing varies with breed, indoor or outdoor life and health, so treat this as a guide. A vet can tell you what suits your cat, and many recommend checks at least once a year, and more often for seniors.

The cat age scale

Just like dogs, cats mature quickly early in life and then age steadily. Veterinary guidance commonly uses a simple scale that is easy to remember: 15, then 24, then 4 more for every year after that.

The scale is based on comparing the stage of development of cats and people, not on a measurement of biological age, so it works best as a guide to what your cat needs at each stage.

A worked example

A 7-year-old cat: the first two years give 24 human years, then 5 more years at 4 each is 20, so 44 in total, which puts the cat at the start of its mature adult stage. A cat of 14 years is 24 + 12 × 4 = 72, a senior. At 18 it is 24 + 16 × 4 = 88.

For kittens, partial years are scaled in proportion: a six-month-old kitten is 7.5 human years, and an 18-month-old cat is 19.5.

Caring for your cat at each stage

Kittens need vaccinations, play and socialising. Young and mature adults benefit from a stable weight, dental care and yearly check-ups. Seniors are prone to kidney disease, arthritis and thyroid problems, which are easier to manage when caught early, so many vets recommend checks every six months.

For a dog, use the dog age calculator, which also takes size into account.

Questions people ask

How do I convert cat years to human years?

The common scale gives a cat 15 human years for the first year of life, 9 more for the second (24 in total) and 4 for every year after that. So a 5-year-old cat is 24 + 3 × 4 = 36, and a 10-year-old cat is 56.

Why does a cat’s first year count as 15?

Kittens reach sexual and physical maturity within about a year, around the age a human teenager is 15. The second year adds a further 9 as the cat settles into adulthood, and ageing then slows to roughly 4 human years per year.

How old is the oldest cat?

Cats that live in comfort with regular vet care often reach their mid to late teens, and a few reach 20 or more. The calculator accepts ages up to 30 to be safe, which on this scale would be 136 human years.

What are the life stages for cats?

The 2021 AAHA/AAFP Feline Life Stage Guidelines describe four stages: kitten (up to 1 year), young adult (1–6), mature adult (7–10) and senior (over 10). Each stage has different needs for food, exercise, dental care and health checks, and an end-of-life stage can come at any age.

Is the calculator suitable for indoor and outdoor cats?

It uses the same scale for both. In practice, indoor cats tend to live longer than cats that roam, but the scale only converts age to a human equivalent and cannot account for lifestyle or health. A vet can give advice on your own cat.