This page discusses how to convert cat age to the equivalent people age. It is specific to domestic house cats, as other types of cats (e.g. wild cats, barn cats, feral cats) age at different rates than our pet house cats.
In addition to showing how to convert cat years, at the bottom of the page the major factors affecting cat health and associated lifespan are described.
Converting Cat Years
There are many tables for converting between cat years (age) and human years (age). Many of them use a very simple calculation (e.g. 1 cat year equals 7 human years). This is inaccurate since the average lifespan for a house cat (excluding accidents, in particular from cars) is about 15 years, whereas the average lifespan for a person (in 1st world countries) is about 75 years. Therefore, a cat year is about 5 human years on average (75 divided by 15).
One also needs to consider that cats spend a relatively small proportion of their lives in the immature stage:
- Cats are physically and sexually developed within about 1 year, whereas people reach the equivalent maturity at 15 years, so the first years of a cats life is equivalent to 15 years of a person's.
- Likewise, at two years of age a cat has reached the same maturity as a person of 25 years, so the second year of a cat's life is equivalent to 10 years (25 minus 15) of a person's.
- Thereafter, each calendar year a cat ages the equivalent of 4 human years.
These factors are expressed in the following table.
||Equivalent Human Years
The oldest recorded age for a cat is 34 years.
Cat Lifespan and Cat Health
The conditions in which a cat lives will greatly affect its lifespan. It is not unusual for a house cat to reach 15 years or even 20 years of age, whereas an intact tomcat living in the wild has an average life expectancy of about 3 years. Some general factors that affect lifespan are:
- Gender. Female cats tend to live slightly longer than male cats.
- Neutering. Neutered cats tend to live longer than intact cats. In part this is due to a reduced risk of cancer, as cancers of the sex organs are often related to sex hormones, which are greatly diminished by neutering. Current research indicates that the sooner the neutering is done the lower the risk of these cancers, and if a female cat is neutered before the first season the risk is believed to be less than 1%. There is also some evidence that neutered cats, especially neutered tomcats, benefit from a reduced exposure to infectious diseases (they stay closer to home).
- Diet. The three major natural causes of death in cats are kidney failure, cancer and infectious diseases. Suitable foods (including special reduced protein cat food for older cats) can significantly delay kidney problems and may also reduce cancers. There are a range of cat foods specially adapted to different cat ages and medical conditions, even a specialty food for neutered cats.
- Living conditions. A suitable environment will result in a healthier cat who can be expected to live longer. For this reason house cats typically live longer than barn cats or feral cats.
- Medical Attention. Cats should have vaccination against the common feline diseases. In some parts of the world the presence of certain deadly parasites (e.g. heartworm) require that cats receive preventive medication monthly to ensure that they are not infected. Infectious diseases is one of the three main natural causes of cat death, which can be easily prevented by ensuring that vaccinations are given and kept up-to-date. Finally, like people, cats periodically require medical treatment for illness or injury, especially as they get older.
- Individual characteristics. Just as some people are born with a strong constitution, so are some cats. Consequently, while one can talk about the expected lifespan of a cat based on the above factors, individual cats will vary somewhat from this.