Dog and Cat Age Calculator
Convert your dog's or cat's age to human years — with size adjustment for dogs and months for puppies and kittens.
This dog age calculator converts your pet's age into human years using veterinary rules rather than the old "multiply by seven" myth. For both dogs and cats the first year of life equals about 15 human years and the second adds about 9 more, so a two-year-old pet is roughly 24. After that cats age about 4 human years per year (International Cat Care), while dogs age at a pace that depends on size: about 4 years per year for small dogs, 5 for medium, 6 for large and 7 for giant breeds, in line with the American Veterinary Medical Association.
Enter the age in years and months — months matter for puppies and kittens, who grow up fastest. For dogs over one year the calculator also shows the DNA-methylation estimate published by UC San Diego in 2020 (16 × ln(dog age) + 31), which was derived from Labrador Retrievers. The age chart below the result lists every year so you can see what lies ahead, and the life stage tells you when senior check-ups become important.
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How do I calculate my dog's age in human years?
Count the first year as about 15 human years and the second as about 9 more (24 in total). From the third year add roughly 4 years per year for small dogs, 5 for medium, 6 for large and 7 for giant breeds. The calculator does this automatically.
Is one dog year really seven human years?
No. The "×7" rule is a myth. Dogs mature very quickly — a one-year-old dog is closer to a 15-year-old teenager than to a 7-year-old child — and then ageing slows down and depends on size.
Why do large dogs age faster?
Large and giant breeds have shorter lifespans, so each year after adulthood counts for more human years. The AVMA notes that small dogs are usually considered senior at about seven years, while large breeds may be senior at five to six.
How old is my cat in human years?
A one-year-old cat is about 15, a two-year-old about 24, and every year after that adds about 4 human years. So a 10-year-old cat is roughly 56 and a 15-year-old cat about 76.
What is the new scientific dog age formula?
In 2020 researchers at UC San Diego compared DNA methylation in 104 Labrador Retrievers with humans and proposed human age = 16 × ln(dog age) + 31. By this formula a one-year-old dog is about 31 and a ten-year-old about 68. It was derived from one breed, so the calculator shows it for comparison only.
How old is a 6-month-old puppy or kitten in human years?
About 10 human years. Development is fastest in the first months: roughly 4 human years at three months and 15 at one year.
What are the life stages of a dog?
Following the AAHA life stage guidelines in simplified form: puppy up to one year, young adult up to three, mature adult until senior age (about 7 for small and medium dogs, 6 for large and 5 for giant breeds), then senior.
What are the life stages of a cat?
International Cat Care describes kitten (up to 6 months), junior (7 months – 2 years), adult (3–6), mature (7–10), senior (11–14) and super senior (15 years and older).
How can I tell a dog's age if I don't know its birthday?
A vet estimates it from the teeth (wear, tartar), eyes (cloudiness of the lens), coat (greying around the muzzle) and body condition. Such estimates are approximate, especially for adult animals.
Is this calculator accurate for every breed?
It gives a veterinary rule-of-thumb estimate. Individual breeds, genetics, weight and health change how fast an animal ages. For health decisions — such as when to start senior screening — ask your vet.