Dog & Cat Age Calculator

Converts a dog's or cat's age into human years and shows its life stage (puppy or kitten, young adult, mature adult, senior). Dogs use a separate chart for each adult weight class.

How to use

1. Choose "Dog" or "Cat" under "Animal". For a dog, pick the "Adult weight" class: small, medium, large or giant.
2. Under "Enter by", choose "Age" and enter the years and months, or choose "Birthday" and enter the date.
3. Read the age "In human years", the life stage and, with a birthday, the "Next birthday".
4. If you have more than one pet, press "Add another pet" to save each one.

How it works

• Dogs use the weight-class chart by Fred L. Metzger, DVM, as printed by IDEXX (2016); cats use the chart of International Cat Care (checked 2026-10-10). Ages between rows are worked out on a straight line.
• Ages under 1 year for dogs and ages past the end of a chart are rough estimates and are marked on the page.
• "Compare with other methods" also shows the AVMA rule of thumb, a DNA methylation formula and the age times 7.
• Results are reference values that vary by breed and animal, not a health assessment. Pet details are saved on this device.

Questions and answers

How old is my cat in human years?

A 1-year-old cat is about 15 in human years and a 2-year-old about 24; after that, add 4 for each year. A 10-year-old cat is about 56.

How old is a 10-year-old dog in human years?

It depends on size. On this chart a small dog is 56, a medium dog 60, a large dog 66 and a giant dog 78.

Is one dog year equal to seven human years?

It is a popular rule with little evidence behind it. On this chart, too, human years rise faster in the early years, and after that they rise faster each year for larger dogs.

At what age is a dog or cat a senior?

Cats are counted as seniors from 10 years. For dogs, senior is the last 25% of the expected lifespan; this tool starts it at 6 years for giant dogs and 8 years for the other sizes.