Enter your dog’s age and size to see the human equivalent — based on modern AAHA Canine Life Stage Guidelines, not the old 1:7 myth.
The first year of a dog’s life is the fastest: a 1-year-old dog is roughly equivalent to a 15-year-old human. By age 2, that is about 24 human years. From then on, aging slows and depends on size — small dogs add about 4 human years per dog year, medium dogs 5, and large dogs 6. This size difference is why a large dog is considered senior years earlier than a small dog.
The chart below shows the human-age equivalent for dogs aged 1–12 years by size, using the same AAHA Canine Life Stage Guidelines as the calculator.
| Dog age | Small dog | Medium dog | Large dog |
|---|---|---|---|
| 1 years | 15 | 15 | 15 |
| 2 years | 24 | 24 | 24 |
| 3 years | 28 | 29 | 30 |
| 4 years | 32 | 34 | 36 |
| 5 years | 36 | 39 | 42 |
| 6 years | 40 | 44 | 48 |
| 7 years | 44 | 49 | 54 |
| 8 years | 48 | 54 | 60 |
| 9 years | 52 | 59 | 66 |
| 10 years | 56 | 64 | 72 |
| 11 years | 60 | 69 | 78 |
| 12 years | 64 | 74 | 84 |
According to AAHA Canine Life Stage Guidelines, small dogs reach the senior stage around 10–12 years, medium dogs around 8–10, and large dogs around 6–8. Large breeds often live 8–12 years while small breeds frequently reach 14–16.
No. The old 1:7 rule overestimates early aging and underestimates later aging. Modern guidelines put a 1-year-old dog at about 15 human years and a 2-year-old dog at about 24.
About 15 years — roughly the human equivalent of a teenager.
About 24 human years. After that, each additional dog year equals about 4–6 human years depending on size.
Yes. Large breeds mature faster and age more quickly: after age 2, a large dog adds about 6 human years per dog year, a medium dog 5, and a small dog 4.
Under AAHA guidelines, a large dog is senior around age 6–8, a medium dog around 8–10, and a small dog around 10–12. The exact age depends on breed.