Dog Age in Human Years
Enter your dog's age and size: the calculator uses modern veterinary coefficients instead of the outdated "multiply by 7" rule.
| Dog's age | Small | Medium | Large | Giant |
|---|---|---|---|---|
| 1 year | 15 | 15 | 15 | 12 |
| 2 years | 24 | 24 | 24 | 22 |
| 3 years | 28 | 28 | 28 | 31 |
| 5 years | 36 | 36 | 36 | 45 |
| 7 years | 44 | 47 | 50 | 56 |
| 10 years | 56 | 60 | 66 | 79 |
| 12 years | 64 | 69 | 77 | 93 |
| 15 years | 76 | 83 | 93 | 114 |
Why the "multiply by 7" rule is outdated
Multiplying a dog's age by 7 gives misleading results: a one-year-old dog is already sexually mature, which hardly matches a 7-year-old child. The American Kennel Club chart, which this calculator uses, counts the first year of a dog's life as roughly 15 human years and the second as another 9 (24 in total), because early growth is extremely fast. From the third year on, aging slows down, and how much it slows depends on the dog's size. Between one year of the chart and the next, the calculator goes in a straight line.
Size and aging: why it matters so much
Curiously, dogs work the opposite way from what we see across species: large breeds age faster than small ones. A Chihuahua can live past 15, while a Great Dane rarely reaches 10: at 10 a small dog is 56 in human years, a large one 66 and a giant one 79. The sizes are the chart's own: small up to 20 lb (9 kg), medium up to 50 lb (23 kg), large up to 100 lb (45 kg), giant above that. Knowing your dog's "human" age helps you spot when the mature and senior stages begin, so you can adjust checkups and diet accordingly. For cats there is Cat age in human years. This tool provides estimates only and is not veterinary or medical advice, always consult your vet.