Dog Age Calculator
How old is your dog in human years? It’s not simply ×7. Enter your dog’s age and size to get a better estimate.
Your result appears here.
By Shah Rukh, software developer · Last updated:
How dog years are calculated
The old “multiply by 7” rule isn’t accurate. Dogs grow up very fast, then age more slowly, and big dogs age faster than small ones. This calculator uses the approach many vets use:
- The first year ≈ 15 human years.
- The second year adds about 9 (so a 2-year-old dog ≈ 24).
- Each year after adds 4 (small), 5 (medium), 6 (large) or 7 (giant) years.
The DNA-based formula
A 2020 study of Labrador retrievers (Wang et al., Cell Systems) compared DNA methylation in dogs and people and suggested human age ≈ 16 × ln(dog age) + 31. It says dogs age extremely fast when young: a 1-year-old dog is like a 31-year-old person.
Frequently asked questions
Is one dog year really seven human years?
No. Dogs mature much faster in the first two years, then more slowly. Size matters too.
When is a dog a senior?
Around 7 years for most dogs, earlier (5–6) for large and giant breeds, and later (10+) for small breeds.
Which dogs live longest?
Small breeds usually live longest, often 13–16 years, while giant breeds average 8–10.
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