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How To Convert Cat Years To Human Years

Is one cat year equivalent to seven human years? Apparently not! Read on to see a more accurate way to determine your cat’s age. We have used a Cat Age Calculator to convert cat years to human years. The results are reported below.

Convert Cat Years To Human Years

Many people think cats age seven human years each year but this an outdated idea. The best way to convert cat years to human years is to estimate that at 2 years of age they are actually 24 years old After 2 years of age, cats age approximately 4 years for every year of their lives. This gives a good estimate of a cat’s human age if it lives indoors.

Why do cats age faster than humans? It is thought the rate at which a body ages is related to metabolic rate, which is related to body size. Cats have high metabolisms with resting heart rates of 140 beats per minute (BPM). Humans have slower metabolisms with a heart rate of 70 BPM. This means cats simply wear out faster than humans.

Below, you’ll find six Cat Years Charts to convert the age of a cat to human years relative to its life stage and lifestyle. The following table gives a simplified overview.

Red tabby asleep

A Quick Comparison of Cat Years to Human Years (approximate)

Cat’s Age in YearsEquivalent Human Age in Years

Of course, many factors can cause a cat to age more rapidly than these estimates, such as living outside, being allowed to roam outside and genetic or contracted diseases.

Cat Life Stages

A cat’s life has 6 stages. The following tables show the age ranges within each stage. (Taken from guidelines developed by the Feline Advisory Bureau and adopted in AAFP Senior Care Guidelines, see references 1 and 2 below)

Kitten – birth to 6 months

Black Kitten
Age of kitten in monthsHuman equivalent in years
0 – 10 – 1
2 – 32 – 4
46 – 8

Junior – 7 months to 2 years

Cat with catnip mouse
Age of cat in monthsHuman equivalent in years

Prime – 3 years to 6 years

Calico cat on its back

After the age of 2 years, whether a cat lives indoors only, is allowed indoors and outdoors, or lives outdoors only, affects how it ages.

Cat age
in years
Human age in years
indoors only
Human age in years
Human age in years
outdoors only

Mature – 7 years to 10 years

Tabby cat on spotted cat bed
Cat age
in years
Human age in years
indoors only
Human age in years
Human age in years

Senior – 11 years to 14 years

White Maine Coon in grass
Cat age
in years
Human age in years
indoors only
Human age in years
Human age in years
outdoors only

Geriatric – 15 years and over

senior cat
Cat age
in years
Human age in years
indoors only
Human age in years
Human age in years
outdoors only

What If You Don’t Know When Your Cat Was Born?

It’s not as easy to calculate a cat age in human years if you’ve adopted from a shelter or taken in a stray. Don’t fret as vets have certain ways to make an educated guess at a cat’s age. They may think you a little strange if you ask, “How old is my cat in human years?” but will use the following methods in an attempt to predict how long your kitty has been alive:


The first place a vet looks to determine a cat’s age is in its mouth to see what condition its teeth are in.

In kittens, teeth can provide a relatively accurate age. A kitten’s incisors appear when it is about 2 weeks old. At 4 weeks, their canines (fangs) cut through. Finally, by 6 weeks their molars appear making a total of 26 teeth. At 11 weeks these deciduous teeth begin to fall out to make way for adult teeth and by about 4 months all the adult teeth are usually present.

Up to 2 years of age, a cat’s teeth are generally quite healthy looking and only mildly stained. After this age, it’s not so easy to use teeth as an age marker as many factors can affect their condition such as breed, diet and whether they have been cleaned on a regular basis.

The older a cat is, the poorer the condition of its teeth. There will be staining, tartar build-up, gingivitis, signs of decay and even missing teeth in older cats.


The lenses can help to determine if a cat is over 6 years of age. At this age, they can often become denser. If you think about it, a 6-year-old cat is about 40 in human years and this is the age when many people begin to develop sight problems.

After 10 years of age, a cat’s eyes often begin to look cloudy if viewed through an ophthalmoscope.

From 12 years, a cat’s irises start to lose their color and uniformity. You will notice different patches of colors and white spots.


Kittens have a softy, downy coat, even if they are eventually to grow into short-haired adult cats. Young cats lose their downy fur but still have soft, silky coats. The older a cat is the courser its coat becomes. Darker fur may show signs of fading, whitening or graying in a senior cat.

Muscle and Skin Tone

Young cats have form muscles and taut skin. The older and more lethargic they get, the more muscle mass they lose. Senior cats, like senior humans, have saggy skin and a bonier appearance unless they are overweight.

Red Maine Coon on window ledge

Can You Predict a Cat’s Lifespan?

There are signs that your cat is aging in a healthy way. You can expect its sleep pattern to change, its stress levels to increase and its vocalizations to change in sound. Its pupils may look cloudier and its iris’s not so uniform in color. Slight weight loss might occur as muscle tone deteriorates and its skin becomes less elastic. Gums redden and teeth look yellow. These changes are all to be expected and a cat can still lead a long and healthy life.

What you need to keep an eye out for is cognitive dysfunction as if left untreated this can shorten a cat’s longevity. If your cat seems lost in familiar surroundings and stops recognizing you and other family members, if it becomes over-clingy or more distant, develops strange sleeping habits, begins to soil around the house, or acts anxious its time to visit the vet as receiving treatment in the early stages of cognitive disorders is more effective.

How Can You Help Your Cat Reach a Ripe Old Age?

Cat lifespan varies widely and many factors affect it. Breed, diet, genetics, health care and lifestyle all play a role. Cats have been known to live past 30 years – that’s 96 in human years. The average lifespan of a cat is 15 years or 76 in human years.

Living an indoor-only life does tend to increase cat life expectancy. This is mainly due to avoiding the perils of the outside world that cats who enjoy a free-roaming lifestyle incur. These include road traffic accidents, injury, poisoning, fighting, and attacks from wild animals.

However, indoor-only cats can suffer from stress and depression through lack of stimulation and diseases related to obesity which are just as capable of shortening their lives.

Cat yawning


Related: How you can really help to lengthen your cat’s life.


1. FAB. WellCat for life veterinary handbook. Tisbury, Wiltshire, UK: Feline Advisory Bureau, 2008: 5. Available at publications/index.php.

2. Pittari, J, Rodan I, Beekman G, et al. American Association of Feline Practitioners’ senior care guidelines. J Feline Med Surg 2009 11: 763–78. ?Id=398 (accessed June 1, 2009).

Grey cat sitting up
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