Pet Age Calculator

Convert your pet's age to human years. Different animals age at different rates compared to humans.

Enter your pet's age to calculate the human equivalent

Override the default ratio (e.g., 7 means 1 pet year = 7 human years)


How Pet Age Calculation Works

The old rule of '7 dog years = 1 human year' is a myth. Different animals age at different rates, and even within species, size matters.

For dogs, we use a scientific logarithmic formula. For cats, we use a formula where the first year equals about 15 human years, the second year adds 10 more, and each year after that adds about 4 human years.

Default Age Ratios

Animal Age Ratio
Small Dog (under 20 lbs) 1 pet year = 5 human years
Medium Dog (20-50 lbs) 1 pet year = 6 human years
Large Dog (50-90 lbs) 1 pet year = 7 human years
Giant Dog (over 90 lbs) 1 pet year = 8 human years
Cat 1 pet year = 4 human years
Rabbit 1 pet year = 8 human years
Hamster 1 pet year = 25 human years
Guinea Pig 1 pet year = 10 human years
Parrot 1 pet year = 1 human years
Horse 1 pet year = 3 human years
Goldfish 1 pet year = 5 human years
Turtle 1 pet year = 1 human years

Frequently Asked Questions

How do you calculate dog years?

Modern science uses a logarithmic formula rather than the old '7 years' rule. Dogs age rapidly in their first two years (a 1-year-old dog is roughly equivalent to a 15-year-old human), then age more slowly. The formula considers that different breeds age at different rates, with smaller dogs typically aging slower than larger breeds.

Is the 7 dog years rule accurate?

No, the '1 dog year = 7 human years' rule is a myth and oversimplification. Dogs mature much faster in their first few years of life. A more accurate approach considers that the first year equals about 15 human years, the second year adds about 9 years, and each subsequent year adds approximately 4-5 human years, varying by breed size.

How do cats age compared to humans?

Cats age similarly to dogs but with slight differences. The first year of a cat's life equals about 15 human years, the second year adds another 9-10 years, making a 2-year-old cat equivalent to a 24-25 year old human. After that, each additional year equals roughly 4 human years.

Do small dogs live longer than large dogs?

Yes, generally small dogs live longer than large dogs. Small breeds can live 12-16 years or more, while giant breeds often live only 7-10 years. This is because larger dogs age faster - their bodies experience more rapid cell growth and aging. A small dog might not reach senior status until 10-11 years, while a large dog becomes senior around 6-7 years.

At what age is a dog considered senior?

It depends on the dog's size. Small dogs (under 20 lbs) are typically considered senior at 10-11 years old. Medium dogs (21-50 lbs) become senior around 8-9 years. Large dogs (51-90 lbs) are senior at 7-8 years. Giant breeds (over 90 lbs) reach senior status as early as 5-6 years old.


Calculate your pet's age in human years. Convert dog years, cat years, and other pet ages to human equivalent.