User Rating 0.0
Total Usage 1 times
Category Pets
Is this tool helpful?

Your feedback helps us improve.

About

The old rule of "one dog year equals seven human years" is a myth. In reality, pets age much faster during their first two years of life and then slow down. Furthermore, size matters immensely - small dogs generally live longer and age slower than giant breeds, who are considered seniors by age 6 or 7.

This tool uses the latest veterinary aging curves to give you a precise equivalent. It accounts for the rapid maturity of puppies and kittens (where the first year is equal to about 15 human years) and the specific aging factors of different weight classes. Knowing your pet's "real" age helps you provide age-appropriate care, nutrition, and medical screenings.

dog age calculator cat years human years converter puppy age

Formulas

There is no single linear formula, but the American Veterinary Medical Association (AVMA) generally accepts:

  • Year 1: Equals 15 human years.
  • Year 2: Adds 9 years (Total 24).
  • Year 3+: Adds roughly 4-5 years per calendar year, depending on weight.

For cats, the formula is more consistent after year 2:

Agehuman = 24 + (Agecat 2) × 4

Reference Data

Pet AgeSmall Dog (Human yrs)Medium Dog (Human yrs)Large Dog (Human yrs)Cat (Human yrs)
1 Year15151515
2 Years24242424
3 Years28282828
5 Years36363636
7 Years44444444
10 Years56606656
12 Years64697764
15 Years76839376

Frequently Asked Questions

Scientists aren't 100% sure, but it seems to be related to the growth hormone IGF-1. Large dogs grow incredibly fast from puppyhood to adulthood, which may accelerate cellular aging and increase cancer risks earlier in life.
Cats are generally considered seniors around 11 years old (equivalent to ~60 human years) and geriatric around 15 years old. Regular vet checkups become critical at this stage.
It is a rough average but very inaccurate for the start and end of life. It underestimates the maturity of a 1-year-old dog (who can reproduce) and overestimates the age of a 15-year-old small terrier.