Pets
Dog Age Calculator
Tell us your dog's age and breed size. We compute their human-equivalent age two ways: the modern logarithmic formula from DNA aging research, and a size-adjusted table closer to what your vet uses.
0–11
Breed size
Medium (20–50 lb)
Modern formula (Wang et al., 2019)
56.8 years
Dog age 5 years
All three are estimates. For health decisions, defer to your veterinarian and use breed-specific charts when available.
Examples
1-year-old medium breed
= 31 (modern) · 15 (table)
5-year-old large breed
≈ 57 (modern) · 42 (table)
10-year-old small breed
≈ 68 (modern) · 56 (table)
How it works
Modern formula · published in 2019, derived from DNA methylation patterns in Labrador Retrievers:
human age = 16 × ln(dog age) + 31
Size-adjusted table · year 1 ≈ 15 human years, year 2 ≈ +9. After that, small breeds add ~4 per year, medium ~5, large ~6, and giant ~7.
For dogs under 1 year, both methods are interpolated linearly. The legacy ×7 rule is shown for comparison only.
Frequently asked questions
No — it's a rough heuristic. Dogs grow up much faster than humans in the first two years, then age more slowly later. We show the legacy ×7 number for context, but the modern logarithmic formula and the size-adjusted table are far closer to reality.
Researchers at UC San Diego (Wang et al., 2019) studied DNA methylation in Labrador Retrievers and proposed: human age = 16 × ln(dog age) + 31. It's accurate for adult dogs and much more biologically grounded than the ×7 rule.
Smaller dogs tend to live longer and age more slowly after middle age, while giant breeds age more quickly. Our size-adjusted table uses widely cited AKC-style figures: ~+4 human years per dog year for small breeds, up to +7 for giants.
For most adult dogs, the modern formula is the best general estimate. For breed-specific or size-specific care decisions, lean on the size-adjusted table — and always defer to your veterinarian.
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