How To Tell A Cats Age. An indoor cat will age approximately 4 human years for every one cat year and an outdoor cat will age approximately. Prime 36 years.
During this time the cat reaches full size and learns about life and how to survive it. Then at around 4 months old the baby teeth start to fall out and adult teeth start to erupt. For the following cat age chart in human years note that overlap between life stages is common and all cats age differently.
Typically all of the adult teeth are in place by 6 months of age and the growth is no longer useful in determining a cats age.
If your cat is over 10 years old all of its teeth will likely show signs of yellowing and they may be worn significantly. This is considered the most reliable method to estimating a cats age. Determining a cats age by teeth over 6 months old can be tricky. The first year of a cats life is equivalent to 15 human years whilst the second year is only equivalent to 10 human years.