There are different ways to calculate a cat's age. The most straightforward method to convert cat years into human years is by dividing the average human lifespan by the average cat lifespan.
An average human lives approximately 83 years.
An average cat lives approximately 15 years.
This gives a factor of: 83 / 15 = 5.5.
This means cat years can roughly be converted to human years by multiplying with a factor of 5.5. For example, a 10-year-old cat would be equivalent to a 55-year-old human.
Maturity: Cat Years in Human Years
However, a cat reaches maturity much faster than a human. That’s why the 5.5 factor doesn’t apply literally to a cat’s early years. A cat is considered “adult” from the age of one. At this age, female cats can also go into heat. So calculating cat years in human years isn’t always exact. We therefore recommend using the 5.5 factor only from the age of 10 and up. For cats aged 0 to 10, it’s best to use the following table.
Cat Years to Human Years
You can use the following table as a guideline.
Kittens:
- 0–1 month: (0–1 human years)
- 2 months: (2 human years)
- 3 months: (4 human years)
- 4 months: (6 human years)
- 5 months: (8 human years)
- 6 months: (10 human years)
- 7 months: (12 human years)
- 12 months: (15 human years)
Adult Cats:
- 18 months: (21 human years)
- 2 years: (24 human years)
- 3 years: (28 human years)
- 4 years: (32 human years)
- 5 years: (36 human years)
- 6 years: (40 human years)
Senior Cats:
- 7 years: (44 human years)
- 8 years: (48 human years)
- 9 years: (52 human years)
- 10 years: (56 human years)
Older Cats:
- 11 years: (60 human years)
- 12 years: (64 human years)
- 13 years: (68 human years)
- 14 years: (72 human years)
Very Old Cats:
- 15 years: (76 human years)
- 16 years: (80 human years)
- 17 years: (84 human years)
- 18 years: (88 human years)
- 19 years: (92 human years)
- 20 years: (96 human years)
- 21 years: (99 human years)
