Dog Age Calculator
Convert your dog’s age to human years with the size-adjusted method, not the old times-seven rule. The first year counts as about 15 human years, then the pace depends on your dog’s size. Every calculation runs in your browser.
Human-equivalent age
29 human years
Adultlife stage
3 yearsdog age
Mediumsize
Medium dogs, by age
| Dog age | Human years | Life stage |
|---|---|---|
| 1 year | 15 | Teenager |
| 2 years | 24 | Adult |
| 3 years | 29 | Adult |
| 5 years | 39 | Adult |
| 8 years | 54 | Mature |
| 10 years | 64 | Mature |
| 13 years | 79 | Senior |
| 16 years | 94 | Senior |
How to use it
1. Enter the age
Type your dog’s age in years, and add extra months if you want a closer estimate.
2. Pick the size
Choose the adult size, because larger dogs age faster in later life.
3. Read the result
See the human-equivalent age and life stage, plus a by-age table for that size.
4. Copy it
Copy a plain-text summary of the result with one click.
Common questions
How is a dog’s age in human years calculated here?
This tool uses a common size-adjusted estimate. The first year of a dog’s life counts as about 15 human years, the second year adds about 9 more to reach about 24, and each year after that adds 4 to 7 human years depending on size: 4 for small dogs, 5 for medium, 6 for large, and 7 for giant breeds. The result is a guide, not an exact biological age.
Is the "multiply by 7" rule accurate?
No. Multiplying a dog’s age by seven is a long-standing myth. Dogs mature much faster than humans in their first two years, then age at a rate that depends on their size, so a flat times-seven number is wrong at almost every age. The size-adjusted method used here reflects that uneven pace.
Why does size change the result?
Small dogs tend to live longer and age more slowly in later life, while large and giant breeds age faster and have shorter average lifespans. That is why the calculator adds more human years per dog year as the size goes up, once the dog is past age two.
How exact is this?
Treat it as a friendly estimate. Real aging varies with breed, genetics, diet, and health, and scientists have also proposed other formulas based on DNA changes. Use this as a rough guide, and ask your veterinarian for advice specific to your dog.