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Cat Years vs. Human Years

Cat Years vs. Human Years: How Old is Your Cat?

The contrast between the cat years vs. human years is one of the most misunderstood relationships between cats and humans. 

As a cat lover, you must have come across the common belief that one human year equals seven cat years. 

Although popular, this misconception doesn’t accurately depict the relationship between cat years and human years. So, how do we contrast cat years vs human years?

Cat Years vs Human Years 

There exists a mathematical relationship between cat years and human years. This relationship allows us to accurately express the age of a cat in human years as follows;

  • The first cat year is equivalent to the first 15 human years.
  • The second cat year is equivalent to 9 human years, and
  • Any subsequent year from the third year henceforth equals four human years. 

Applying this logic, we estimate three cat years to be equivalent to twenty-eight (28) human years, as shown in the tables below;

Cat Years Human Years
1 15 
2 24
3 28
4 32
5 36

Why Should You Know Your Cat’s Age?

While our cats may be eternal kittens in our eyes, knowing how old they are can help us provide them with the best care. 

Like humans, cats’ health and nutritional needs change as they age. Knowing your cat’s age will give you the advantage of knowing and anticipating these changes and, therefore, taking better care of your pet. 

Kittens would usually require diets with high proteins for growth and development. In this infant stage, kittens feed exclusively on milk. 

Junior adults and adult cats should consume proteins and limited calories to control weight gain at maturity. On the other hand, older cats might require additional nutritional supplements like vitamins. 

By knowing your cat’s exact age, you can make informed decisions on how and what to feed it.

Similarities Between Cat and Human Years

While cat years and human years might be counted differently, the two exhibit some notable similarities such as;

1. Growth stages

Both cat and human years feature similar growth stages, with infancy as the first stage, followed by adolescence, adulthood, and old age. 

Kittens below six months are considered to be infants. This stage is equivalent to the first 15 years of human life. 

For the first month, kittens feed exclusively on breast milk. Weaning begins after six weeks, starting with moistening kitten feed.

Adolescence in cats occurs at the age of 7 months to 2 years. This phase corresponds to human ages between 11 and 27 years. 

At seven months, cats are almost physically and sexually mature and are often playful with a desire to explore and play.

 If not sterilized, cats within this growth stage will exhibit signs of sexual activity, including loud meowing and general restlessness in females. Males will often become more aggressive toward each other and form a habit of escaping in search of mates. 

Cats become adults between the ages of 3 and 7 years. This is equivalent to 28 to 43 human years. Both energy levels and sexual activeness remain high through this stage until the maturity ages of 7 to 10 years. 

The maturity age is equivalent to a person of   44 to 59 years. At this stage, a cat in this phase progressively reduces its energy levels and desire to play, dedicating more time to rest. 

Beyond ten years, a cat enters the senior growth phase, equivalent to 60 – 75 human years. At this stage, cats tend to rest more and play less. 

It is common for chronic diseases to develop. From this stage, cats become susceptible to more severe conditions like tumors, drastically affecting their quality of life.      

2. Physical and Cognitive Changes

Both humans and cats undergo physical and cognitive changes as they age. Cats’ growth and development cycle closely resembles that of humans. 

As these changes occur, so do their nutritional requirements through the various growth stages. 

As infants, kittens depend entirely on their mothers for nourishment and learning. As adolescents, they become more independent as they attain sexual maturity. 

Differences Between Cat and Human Years 

Although cat years have a few similarities to human years, the two are set apart by two significant differences;

1. Rate of aging

While human beings are considered to age at a constant rate throughout their lives, cats age way faster in their early years than humans. 

This contrast is clearly represented in the table above, where the first year of a cat is equivalent to fifteen human years. However, after the second year, the cat’s aging rate drops to a constant rate of four human years for each cat year. 

2. Lifespan

Cats have a considerably shorter lifespan compared to humans. While humans can live to more than 120 years, cats have an average lifespan of only human years. Factors like genetics, healthcare, and nutrition also determine cats’ lifespan. 

Indoor cats tend to live longer, with an average life expectancy of 16 to 18 human years. If well taken care of, cats can exceed this expectancy as for the case of the oldest cat with a record of 34 human years!

In contrast, most outdoor cats have an average life expectancy of 13-14 human years. Although nature takes care of its own, these wild felines lack the nutrition and healthcare to guarantee a longer life. 

Estimating Your Cat’s Age 

In scenarios where the actual age of a cat is unknown, It is possible to come up with a reasonable estimate. The most common approach entails calcifying your feline into age brackets based on its appearance. 

While this approach can give a reasonable estimate, it’s only reliable when estimating ages less than eight months. You can tell the cat’s age by looking at;

1. Teeth

Like all mammals, dental formation in cats occurs within predefined ages. While teeth can’t give us the exact age, they can reasonably approximate it. 

The first set of incisors milk teeth in kittens appear between the first 2-4 weeks of age, followed by canines between the third and the fourth weeks. 

Pre-molars appear between the fourth and the sixth week followed by molars, a fortnight later. A kitten should have developed a complete set of milk teeth at eight weeks old. 

Kittens start shedding off their dentures at four months and develop permanent teeth by the sixth month. Estimating the exact age of your cat older than six months is difficult, but there are still hints you can look out for. 

For instance, yellow stains (tartar) on some teeth date the cat to ages between one and two years. On the other hand, pronounced stains on all teeth indicate periods between 3-5 years. 

 Cats between the ages of 5-10 are known to have high tartar build-up with worn-out teeth. Older cats over ten years of age tend to have missing teeth. It’s important to note that sometimes cats have dental issues that misguide our estimations. 

2. Shape and Size

There is a rule of thumb that for the first six months, kittens gain a pound of body weight monthly. Assuming his rule holds, a six-month-old kitten should weigh approximately 6 lbs. 

Just like with teeth, we can only rely on body shape and size for accurate estimates below the age of six months. Also, other factors like diet can influence the amount of weight gained by your kitten. 

3. Eyes

Kittens tend to have smooth, clear lenses, which become cloudy as they age. Unlike teeth, placing the transition in a specific time frame is impossible. However, it’s known that cloudy eyes and jagged iris are signs of aging in cats.

Cats also develop eye complications like cataracts in their advanced ages. The presence of such conditions is a clear indication of advanced aging.

4. Coat development 

Kittens fur is characterized to be soft and baby-fine and it thickens as the cat ages. The coat color might change to a darker or lighter variation. 

Additionally, kittens tend to have light, tight coats with toned muscles. As the cat ages, the skin becomes baggy and coarse.  

5. Activity Level

Cats display different levels of playfulness through the various growth stages. Generally, kittens tend to be more energetic and playful compared to older cats. 

While it is expected to find kittens climbing up and down walls and playing with toys, older felines prefer sleeping.  


Understanding the relationship between cat years’ vs human years is critical to caring for your feline friend. Accurately estimating your cat’s age allows you to adjust its diet to meet its nutritional needs. 

Even better, you don’t have to struggle with the math yourself. There are plenty of online tools that you can use to convert your cat’s age into human years. 

If you don’t know the exact age, then you can follow this guide to estimate based on its anatomy accurately. 

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