Cat Age Calculator: Cat Years to Human Years, by Month

Multiplying by seven gets cat ages badly wrong. Cats race through childhood: a one-year-old cat is roughly as mature as a 15-year-old person, and by its second birthday it is about 24. After that each cat year counts for about four human years. Pop in your cat's age below, down to the month for kittens, to get its human-equivalent age, its life stage and what that stage means for vet visits.

The conversion follows the chart vets in the UK and US use: International Cat Care's age table and the AAHA/AAFP convention of 15 human years at age one, 24 at age two, then four a year. The life stages come from the 2021 AAHA/AAFP Feline Life Stage Guidelines. It works the other way too, if you want to know how old a cat would have to be to "match" your own age.

Cat age chart: cat years to human years

Why the first two years count for so much

A kitten goes from helpless newborn to sexually mature in around six months, and has finished growing by about a year. A person takes well over a decade to cover the same ground, which is why the early months convert at such a steep rate. Once a cat is fully adult the ageing settles into a steadier pace, and four human years per cat year is the figure used from then on.

Unlike dogs, where a Great Dane and a Chihuahua age at very different speeds, cats are similar enough in size that one chart works for almost every breed. Indoor cats tend to avoid road accidents and fights, so they often live longer, but they do not age more slowly; the conversion is the same.

How long do cats live in the UK?

A 2024 Royal Veterinary College VetCompass study of UK cats put average life expectancy at birth at 11.74 years, with plenty living well into their late teens. Reaching the senior stage is normal, which is why the checks that come with it matter: kidney disease, an overactive thyroid and high blood pressure are all common in older cats and all respond better when caught early.

If you need care while you are away, our guides on cat boarding costs and questions to ask a cattery cover what an older cat needs from a stay, and how to find a good vet helps if you are looking for a practice that suits a senior cat.

Common questions

Is one cat year equal to seven human years?

No. The seven-times rule understates young cats and overstates older ones. A one-year-old cat is closer to 15 than 7, and a ten-year-old is around 56 rather than 70.

At what age is a cat a senior?

The AAHA/AAFP guidelines class a cat as a senior once it is past its tenth birthday. Many UK vets start offering senior clinics or extra checks from around that age.

How do I tell a rescue cat's age?

A vet can estimate it from teeth, eyes, coat and muscle tone. Adult teeth are all through by around six months, and tartar and wear build up after that, but beyond early adulthood the estimate is usually a range of a few years rather than an exact figure.