Although veterinarians and other experts can only estimate the relationship between cat years and people years based on the ways in which cats age and mature, they have a pretty good sense of feline-human age equivalents.
The length of a cat year in relation to a human year actually varies over the lifespan of the cat. Cats progress rapidly through human-year equivalents during their first year of life, after which the process slows as they age.
Kitten Ages in Human Years
According to Tracie Hotchner (The Cat Bible, 2007), a one-month-old kitten can be likened to a 6-month-old human baby. At this age, kittens cannot use a litter box and they are still nursing. By three months, a kitten is more akin to a 4-year-old human child. By this age, kittens are normally litter trained and mostly or completely weaned.
Hotchner believes that a 6-month-old kitten is approximately 10 human years of age. However, there are other experts such as Arnold Plotnick, DVM (2011), who equate 6 months with 15 human years (Hotchner equates 8 months of kitten life with 15 years of human life). Plotnick’s estimate may be more precise, given the fact that many kittens are physiologically capable of becoming pregnant as early as 5 or 6 months of age. This suggests that by 5 months, many kittens have reached the equivalent of the tween or early teen stage of human life.
One-year-old kittens have reached the equivalent of human young adulthood – 18 human years of age – according to Hotchner. Plotnick asserts that cats are even older at this age, equating 1 year of cat life to 24 years of human life. It should be noted that there are a few breeds, such as the Maine Coon, that don’t reach their full size until they are several years old, but they are physiologically capable of having kittens at a much younger age.
Adult Cat Years in Human Years
Once cats reach adulthood, the accelerated aging process in relation to human aging beings to slow. Hotchner provides the following conversion:
- 1 = 18
- 2 = 24
- 4 = 35
- 6 = 42
- 10 = 60
Veterinarian Arnold Plotnick asserts that cats are older at one year than many others believe, but suggests that the process slows even more rapidly as cats age. He provides the following conversion whereby adult cats age approximately 4 years for every human year:
- 1 = 24
- 2 = 28
- 3 = 32
- 4 = 36
- 5 = 40
- 6 = 44
- 7 = 48
- 8 = 52
- 9 = 56
- 10 = 60
Many owners find that 10-year-old cats, despite having reached the equivalent of human early retirement age, are still quite playful. Like humans, cats that are active as they age tend to be healthier. Playing regularly with senior cats can help them to stay active.
Cat Years and Human Years in Old Age
Past age 10, a cat is considered to be a senior. Hotchner provides a conversion only to 16 years, equating a 12-year-old cat with a 70-year-old human, a 14-year-old with an 80-year-old, and a 16-year-old with an 84-year-old. Plotnick provides a more detailed comparison, with each year representing approximately 4 additional years:
- 11 = 64
- 12 = 68
- 13 = 72
- 14 = 76
- 15 = 80
- 16 = 84
- 17 = 88
- 18 = 92
- 19 = 96
- 20 = 100
With better veterinary care and more cats being kept indoors, many cats live into their mid or late teens these days, and there are even plenty of cats in their early 20s. Breeds such as the Siamese and Manx are known to be particularly long-lived, though any indoor cat that receives good veterinary care and eats a premium, high-protein diet has a good chance at a long, healthy life.
The photos below depict the same cat at various ages, ranging from 4 weeks to 20 years of age (this cat is 21 years old now and still going strong). As can be seen from the photos, a cat may still be playful well into old age.
References:
- Hotchner, T., The Cat Bible: Everything Your Cat Expects You to Know, London, Penguin Group, 2007.
- Plotnick, A., DVM, “How Old Is My Cat in Human Years?” CatChannel.com, 2011.
Jennifer Copley - Jennifer Copley, BFA, BEd, has a diverse base of expertise that includes research, writing, education, pet care, and various other ...
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