In Words: How do you measure a cat’s age?

There isn’t an easy-to-remember formula for working out a cat’s age because the progression of ageing is not linearly aligned to human age. You’ll see what I am trying to say if you read the rest of this short page 😉 .

Human equivalent of cat age in words

Picture left: Michael. Picture right: copyright Helmi Flick

Some people might use a simple formula like one human year is four cat years so a 20 year old cat is 80 years of age by our standards but it doesn’t work across all the ages of the cat. Ruth’s chart divides up a cat’s life into three age groups: kittens, adults, seniors because during each phase the aging process is different.

So, for example, a one-year-old cat is actually equivalent to a 15 year-old teenage person in terms of physical and mental maturity. Using a straight formula it would mean saying that one cat year equals 15 human years which can’t be true because a ten-year-old cat would be aged 150. The first year of a cat’s life the ageing/maturing process is speeded up when compared to us.

The first year of a cat’s life is comparable to the time a person takes to reach the early stages of adulthood. As for human adolescents a one-year-old cat looks more or less grown up and physically able to be a parent but is mentally immature.

In year two of a cat’s life she enters the equivalent of adult human life i.e. mid-twenties.

Thereafter, a cat aged three is still relatively young being equivalent to a person of twenty-nine. A cat aged six equals a person aged forty-one (middle-aged effectively) while a cat who is twelve years-of-age is similar to a human who is around sixty-five years old: just retired and about to slow down a bit.

These are still generalised statements because as always we have to remind ourselves that cats are individuals just like us. The genes come into play when it comes to longevity. Lifestyle – environmental issues – also affects age. We know that domestic cats live much longer on average than feral cats but not many feral cats die of old age.

Note: sources for news articles are carefully selected but the news is often not independently verified.

Michael Broad

Hi, I'm a 74-year-old retired solicitor (attorney in the US). Before qualifying I worked in many jobs including professional photography. I love nature, cats and all animals. I am concerned about their welfare. If you want to read more click here.

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2 Responses

  1. Marc says:

    Yeah I think the teeth are the best way to tell – just that even that is not easy. The amount of times I have heard people say that they were told their cat was a certain age but later the cat gets sick or has teeth removed and they are told that actually the cat is alot older than they thought.

    I think even with the teeth to go by they still get it wrong by a good 5 or more years sometimes. So it’s just not easy and depends on the cat’s life and health til that point. A cat from the streets who has survived alot will look much older than an indoor cat the same age because his body is literally more used up. Little kittens have the softest toe pads – and gradually they change. But when they live indoors alot they stay much softer for much longer. The calculation must therefore include as much background information as possible in order to get closer to knowig their true age.

  2. dmricciardi says:

    If I rescue a kitty, and don’t know his/her age, I generally go by teeth and activity levels as well as discussing it with my vet to get an approximate age for them (in human years). . .then I give them an approximate birthday!! <3

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