Dog Age Calculator
Enter your dog's age and choose its adult size. The calculator gives the equivalent age in human years, since small dogs and large dogs age at different rates.
Type a number and the answer appears straight away.
Age in human years36Adult
- By the old multiply-by-7 rule
- 35
- By the 2019 DNA study formula
- 57
An approximate guide. Dogs mature fast in their first two years, then large breeds age more quickly than small ones. The DNA study formula (16 x ln(age) + 31) was based on Labrador retrievers.
| Dog's age | Small | Medium | Large | Giant |
|---|---|---|---|---|
| 1 | 15 | 15 | 15 | 12 |
| 2 | 24 | 24 | 24 | 22 |
| 3 | 28 | 28 | 28 | 31 |
| 5 | 36 | 36 | 36 | 45 |
| 7 | 44 | 47 | 50 | 56 |
| 10 | 56 | 60 | 66 | 79 |
| 12 | 64 | 69 | 77 | 93 |
| 15 | 76 | 83 | 93 | 114 |
The math behind it: Dog Age
the first year counts as about 15 human years, the second as about 9, and each later year as 4 to 7 depending on size
A 5-year-old medium-sized dog is about 36 in human years, and a 10-year-old large dog is about 66. Dogs grow up very quickly in their first two years, after which large breeds age faster than small ones.
This is an approximate guide based on the chart published by the American Kennel Club. Breed, health and lifestyle all make a difference.
Common questions
How do I calculate my dog's age in human years?
Count the first year as 15 human years and the second as 9. After that, add about 4 years for each year of a small dog's life, 5 for a medium dog and 6 for a large dog.
Is one dog year really seven human years?
No. The multiply-by-seven rule is a rough average that underestimates young dogs. A one-year-old dog is closer to a 15-year-old person than a 7-year-old.
Do small dogs live longer than big dogs?
Generally, yes. Small breeds often live 12 to 16 years, while giant breeds may live only 7 to 10, which is why large dogs count as seniors sooner.
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