Dog Age Calculator
Last updated: 2026-06-25
A dog's human age is about 15 years at age 1 and about 24 years at age 2, after which 4 to 6 human years are added per year depending on breed size.
The formula is human age = 24 + (dog age − 2) × per-year factor by size (small 4 / medium 5 / large 6). (For dogs aged 2+, an estimate for reference only.)
Enter dog details
Human age conversion
0 yrs
The human-age conversion is an estimate for reference only that varies by breed and individual. For a health assessment, consult a licensed veterinarian.
How to use
- Enter dog age — Enter your dog's age in years (or as a decimal).
- Select breed size — Choose small, medium, or large to match your dog.
- View the result — Press calculate to see the human-age conversion and life stage.
How to convert dog years to human years
Dogs grow far faster than humans. In the first one to two years especially, they pass through the equivalent of human adolescence and early adulthood, and after that their rate of aging varies by breed size. That is why the old rule of simply multiplying every age by 7 differs greatly from reality.
This calculator uses a widely adopted conversion model. It treats age 1 as about 15 human years and age 2 as about 24, and after age 2 it adds 4 (small), 5 (medium), or 6 (large) human years per year by breed size. For dogs under 1 year, growth toward about 15 human years over the first year is converted proportionally.
| Dog age | Small | Medium | Large |
|---|---|---|---|
| 1 yr | 15 | 15 | 15 |
| 2 yrs | 24 | 24 | 24 |
| 3 yrs | 28 | 29 | 30 |
| 5 yrs | 36 | 39 | 42 |
| 7 yrs | 44 | 49 | 54 |
| 10 yrs | 56 | 64 | 72 |
| 13 yrs | 68 | 79 | 90 |
As the table shows, at the same age a large dog converts to a higher human age, because large dogs age faster and have shorter average lifespans than small dogs. To learn more about how dog age maps to human years, see the How Old Is My Dog in Human Years? guide.
Frequently asked questions (FAQ)
How old is a 1-year-old dog in human years?
Dogs grow rapidly in their first year, so regardless of breed size a 1-year-old dog is about 15 human years. At 2 years it is about 24, and after that 4 to 6 human years are added per year depending on breed size.
Why is the old 'multiply by 7' rule inaccurate?
Dogs mature much faster when young and age at different rates by breed size in their senior years, so multiplying every age by 7 differs greatly from reality. This calculator reflects the rapid growth of the first 1 to 2 years and the size-based difference in aging.
Why are human ages different for large and small dogs?
In general, large dogs age faster and have shorter average lifespans than small dogs. So at the same age, a large dog's human-age conversion is higher. This calculator converts using small, medium, and large brackets.
At what age is a dog considered a senior?
In general, small dogs are seniors at around 8 to 10 years, medium dogs at around 7 to 8 years, and large dogs at around 6 to 7 years. Regular checkups and diet management matter in the senior years, so consult a veterinarian.
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Last updated: 2026-06-25