At 2 years old, cats are thought to be fully grown and completely mature-the equivalent of a human in their early to mid 20s. After age 2, a cat ages at a slower and more steady rate when compared to a human. For every year of the cat's life after age 2, one cat year equals approximately 4 human years. This is based on how cats mature-for example at around 10 - 11 human years most cats start to slow down quite a lot... This is when they're getting to about 60 years old in Kitty terms. However, there are a few things to bear in mind when using this cat years to human years calculator:
http://www.cat-behavior-explained.com/cat-years-to-human-years.html
1 One can compare a cat of 16 to an 80-year-old human. 2  A kitty at 16 or older is moving and thinking more slowly than he once did, and he probably has a few age-related health issues. 3  He’s likely not as alert or responsive as he once was.
http://healthypets.mercola.com/sites/healthypets/archive/2014/09/22/senior-cat-care.aspx
Print. By Dr. Becker By the time your cat reaches the age of 10, she’s officially a feline senior citizen. The good news is that many cats today are living into their late teens and even early 20s. With the proper care, a kitty in good health at 10 can easily live another 8, 10, or even 12 years.
http://healthypets.mercola.com/sites/healthypets/archive/2014/09/22/senior-cat-care.aspx
A cat at one year of age is thought to be about 15 in human terms, as cats reach full sexual maturity at one year, whereas humans reach it at about age 15.
http://www.cat-behavior-explained.com/cat-years-to-human-years.html
When a cat is nearly 1 year old, they are approximately 15 human years old. When the cat reaches 2 years old, he is approximately 24 years old. An indoor cat will age approximately 4 human years for every 1 cat year and an outdoor cat will age approximately 8 cat years for every 1 human year.
http://blog.adoptandshop.org/determining-a-cats-age/
It can be difficult to tell how old your cat is if you haven’t had him since birth. I adopted a cat and was told he was 3 years old, but after spending about a year with him, I think he was closer to 8 years old. His age was not a determining factor in his adoption luckily! It is helpful to know roughly how old your kitty is so you can provide better age appropriate care.
http://blog.adoptandshop.org/determining-a-cats-age/
Story at-a-glance 1  +. Cats are officially “seniors” by the time they reach 10 years of age. 2  Fortunately, kitties today often live well into their teens and even their early 20s, so a 10-year-old healthy “senior” cat still has lots of living left to do!
http://healthypets.mercola.com/sites/healthypets/archive/2014/09/22/senior-cat-care.aspx
1 The first teeth to grow in a kitten are the incisors (around 2-4 weeks) and canines (around 3-4 weeks), followed by the premolars (around 4-6 weeks). 2  A cat younger than around four months will not yet have its molars. 3  From the ages of around six months up to one year, your cat will have all of its adult teeth.
http://www.wikihow.com/Know-Your-Cat%27s-Age
Older cats may be saggier skinned and bonier on the rump or shoulder blades. It is said that a cat who lives outdoors ages nearly twice as fast as an indoor cat. At 14 cat years old, an indoor only cat would be 72 human years old, an outdoor cat would be 120 years. This rate of aging kicks in around the 3 year mark. Whether indoor or outdoor, a cat ages a lot the first 2 years.
http://blog.adoptandshop.org/determining-a-cats-age/
1 Frequent checkups in which your vet performs a complete geriatric workup are essential to maintaining your cat’s good health. 2  One can compare a cat of 16 to an 80-year-old human. 3  A kitty at 16 or older is moving and thinking more slowly than he once did, and he probably has a few age-related health issues.
http://healthypets.mercola.com/sites/healthypets/archive/2014/09/22/senior-cat-care.aspx
how old is a cat year
One cat year equals approximately 4 human years.