Cat Years to Human Years: How Old Is My Cat, Really?

7 September 2021

How old is my cat, and how long can cats live? If you've ever found yourself wondering about your cat's age in human years, this is the article for you.

brown old cat outside in tree

If your cat is a rescue, you’re bound to find yourself wondering How old is my cat? While the number may not matter, having some idea of your cat’s age (from cat years to human years) can help you anticipate their needs and provide them with everything they require for a healthy and happy life. 

Below you’ll learn how cat’s age in relation to humans, simple tips for honing in on your cat’s age, the signs of a senior cat, how long cats live, and what you can do to help ensure your cat lives a long life at your side. And while you’re here, check out how to keep outdoor cats safe

How to calculate cat age in human years

It’s commonly stated that one human year is the equivalent of 7 cat years. This is an effort to demonstrate that cats age more quickly than humans. However, they do not age proportionately.

Cats reach maturity at a much faster rate than humans in the beginning of their lives. Once they reach adulthood, their aging slows down.

It’s difficult to draw a direct comparison between a cat’s age and its human equivalent, but the general consensus is that a cat ages the equivalent of 15 human years in the first year of their life.

By the end of their second year, a cat is thought to be the equivalent of 24 or 25 human years.

From 2 years on, experts believe cats age at a rate of approximately 4 human years per cat year

Cat years chart: Cat years to human years

Keeping track of your cat’s aging can be confusing, so we’ve created this handy chart to help you convert cat years to human years. Understanding how old a cat is in human years can help you understand their current life stage and better predict their needs. 

convert cat years to human years: cat years chart

How to tell how old a cat is if you don’t know when they were born 

Even if you can’t be sure when your cat was born, it’s still possible to determine their age with relative accuracy. The state of your cat’s teeth, coat, muscle tone, and eyes all offer insight into their age.

Using the tips below, you can work to identify your cat’s life stage and then make an educated guess as to exactly how old your cat is. 

How to tell a cat’s age by their teeth

A cat’s teeth can be telling when it comes to determining their age. Adult cats have 30 teeth, while kittens have 26 baby teeth (also known as deciduous teeth).  

Kittens develop their first teeth between 2 and 4 weeks of age. By 6 weeks of age, kittens should have all of their deciduous teeth. Between 4 and 7 months of age, the deciduous teeth are replaced by adult teeth.  

Counting a cat’s teeth is a good place to start when trying to gauge their age. Once you determine whether the cat is a juvenile or an adult, you can use other characteristics to further narrow in on their age.

The color of a cat’s teeth and the amount of tartar present can also help indicate how old they are. Cats between 1 and 2 years of age often have some yellowing on their teeth, but tartar buildup should still be minimal. Beyond 3 years, you may see tartar buildup around the base of each tooth.

This is not a perfect science though, since cats with excellent dental hygiene will not exhibit much tartar, regardless of age.

Dark stains on a cat’s teeth or missing teeth could be indicative of a senior cat (one over 11 years old)

What a cat’s coat says about their age

As cats age, their coats often begin to show some gray. In cats with light-colored coats, this change may not be noticeable, but for cats with dark coats, you’ll begin to see some grey or white hairs where there weren’t any before.

Older cats may begin to neglect their frequent grooming routines, leaving their coat looking dirtier or duller than it otherwise would. 

It’s not uncommon for a cat’s fur to change texture as they get older. The fur may become thinner, less glossy, or more coarse. Sometimes these changes can be indicative of a health issue, such as kidney problems or malnutrition, so if you notice sudden changes, don’t hesitate to contact your veterinarian. 

Muscle tone – another cat aging factor

Muscle tone is another indication of how old your cat is. Kittens are typically quite lean and have not yet accumulated much muscle mass. Healthy adult cats typically have good muscle tone. They shouldn’t have protruding bones, and their spine should be straight. 

As cats enter their senior years it’s not uncommon for them to begin losing muscle. You may notice your senior cat’s shoulder blades or hip bones begin to protrude more than they did previously. Often, senior cats aren’t as active as they once were (perhaps due to the aches and pains of aging) and thus they spend more time sleeping and less time exercising. Naturally, this leads to a loss in muscle definition.

While some muscle loss is normal, excessive muscle loss could be an indication of a serious health issue. Cats with poor nutrition or health problems such as kidney disease could struggle to maintain body weight and muscle tone. If you notice a sudden, significant decline in muscle mass in your aging cat, speak to your veterinarian. 

Cat’s eyes and the aging process

Clear, bright eyes are a sign of a young cat. As cats age, they may develop cataracts or glaucoma, leading to discoloration or cloudiness of their eyes. Senior cats often have more eye discharge than a kitten or adult cat. Sometimes a cat’s irises will change shape too, beginning to look jagged around the edges rather than smooth.    

brown old cat close up of face

How do cats age?

As you can see in the chart above, cats undergo the biggest age-related changes in the first couple of years of their lives.

By the end of year one, cats are said to be comparable to a 15-year-old human. Within this period, a cat goes from a newborn kitten with closed eyes and no teeth to a young adult cat who has reached sexual maturity. 

Cats are said to age approximately 9 human years in their second year of life, making them the equivalent of a 24-year-old human by the time they are 2 years old. 

Two-year-old cats have reached sexual maturity, and they have stopped growing. By this time they have accumulated muscle mass and are settling into their adult physique. 

After two years, cats age more gradually, at a rate equivalent to about 4 human years for each cat year.

Once cats reach about 11 years old they are considered senior citizens. They are now the equivalent of a 60-year-old human. Around now, your cat may begin to show signs of aging, such as a decline in physique, graying fur, and changes in their eyes, teeth, and coat. 

Senior cats continue to age at a rate of about 4 human years per cat year. 

Signs of a senior cat 

Just like in humans, there are some tell-tale signs of senior status among cats. While senior cats are often still healthy and full of life, they may begin to slow down a little. As your cat transitions into senior status, it’s important to take note of any changes as drastic shifts could be indicative of serious health conditions.  

Senior cats may exhibit:

  • Stiffness and decreased mobility
  • Cloudy eyes
  • Dull coat
  • Excessive eye discharge
  • Weight loss and loss of muscle tone
  • Frequent urination
  • Confusion or disorientation

Beyond physical decline, senior cats may also exhibit dementia. Some common signs of feline dementia include frequent meowing, disorientation, and excessive sleeping.

Senior cats can still have many wonderful years ahead of them, so don’t be discouraged or distraught if your cat is starting to slow down. Simple lifestyle tweaks, such as specially formulated food can help your senior cat make the most of their twilight years.

How long can cats live? How long do cats live on average?

Cats have an average life expectancy of 16 to 18 years, though some cats may live even longer. In fact, according to the Cornell Feline Health Center, many cats live to be 20 or 21. 

Certain cat breeds are known to have notably long life expectancies while some are more susceptible to certain health issues than others. For instance, both Siamese and Savannah cats are said to have a life span as long as 20 years. Meanwhile, Ragdoll and Persian cats are both susceptible to Polycystic Kidney Disease (PKD)

According to the UC Davis Department of Veterinary Medicine, indoor cats are expected to live much longer than outdoor cats. This is largely because indoor cats face fewer hazards than cats who live outdoors. Outdoor cats are vulnerable to threats like predators, traffic, toxins, and diseases from other animals that indoor cats may never come into contact with. Keep outdoor cats safe with these tips.

brown old cat outside in tree

Of course, nothing is ever guaranteed. Even indoor cats that are extremely well cared for may fall ill unexpectedly, while breeds that are highly prone to certain health afflictions may never be affected by them. As frustrating as it may be, there’s just no way of knowing how long your cat will live

Feeding your cat a balanced diet and ensuring they maintain a healthy body weight can help increase your cat’s life expectancy and keep them agile and active well into old age.  

How to make your cat live longer? 

Naturally, we all want our pets to live forever. While we can’t promise this, there are simple things you can do to help ensure your cat lives a long and fruitful life.

Just as with humans, diet and exercise are a big part of your cat’s longevity. They are also two of the few aspects you have control over. 

Feeding your cat a high-quality, balanced diet will help them stay healthy and happy throughout each stage of their life. And keep in mind that as cats age, their dietary needs change. So speak to your vet about how to provide the best nutrition for your cat in their current life stage. 

Moreover, physical activity is also essential for good feline health. You may decide to let your cat outside for this reason. In this case, a Tractive GPS cat tracker can be a lifesaver. The cat tracker not only shows you where your cat is at all times, but also allows you to see how much physical activity they get. These insights can help you notice any changes in your cat’s habits, allowing you to swiftly address abnormal behavior and make any necessary lifestyle tweaks.

outdoor cat wearing Tractive GPS cat tracker
Keep your cat safe with a Tractive GPS tracker for cats

With these tips, you’ll be able to determine your cat’s age and provide them with everything they need to thrive during this stage in their life. 


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