How to Calculate A Cat's Age in Cat Years
A cat reaches the approximate human age of 15 during its first year, then 24 at age 2. Each year thereafter, it ages approximately four "cat years" for every calendar year. Thus, a 5-year-old feline would be approximately 36 in cat years.
Note: It should be remembered that a cat who lives outdoors ages far more quickly, perhaps even twice as fast, than an indoor cat. Scroll to the bottom of this article to see a chart for easy comparison.
Indicators of a Cat's Age
If you've taken in a stray or adopted a cat whose age is unknown, there are some ways to determine her age. Here are some things vets check to get a general sense of how old a cat is:
The Teeth: Teeth are a great indicator of age. Older cats tend to have more staining than younger cats, assuming the previous owner was negligent in brushing the cat's teeth. And a kitten's teeth first come in between two to four weeks; their more permanent set appears at around four months of age. So if you open a cat's mouth and find permanent, white teeth, the feline is likely to be around a year old. Some yellowing might place the cat between 1 and 2, and tartar build-up on all the teeth indicates that the cat could be between 3 and 5. Missing teeth may mean you have a senior cat on your hands.
Muscle Tone: Younger cats are more likely to have some muscle definition from their higher activity level. Older cats are usually a bit bonier and may have some extra skin hanging or protruding shoulder blades.
The Coat: A younger cat usually has a soft, fine coat, whereas an older cat tends to have thicker, coarser fur. A senior cat may display grays or patches of white.
The Eyes: Bright, clear eyes without tearing or discharge are common in younger cats. A cat with some cloudiness in their eyes is likely to be 12 years old or so. While inspecting the lens, also examine the iris of the eye. Young cats have smooth irises, while the iris of an old cat can sometimes appear somewhat jagged
A Cat's Life Span
Felines are generally quite long-lived, though mileage varies depending on owner maintenance and genetic predisposition. In a handful of documented cases, cats have exceeded 30 years in age. Typically, indoor cats may live 12 to 18 years, with many surviving into their 20s. Outdoor cats face greater threat of accident and/or illness, and average roughly 10 years.
Use the chart below to calculate your pet's age: