Forget the "multiply by 7" rule
The popular rule of multiplying a dog's age by 7 has no solid scientific basis. Dogs mature much faster in their first years and then slow down — aging isn't linear.
The formula used (UCSD study, 2019)
Researchers at UC San Diego, comparing epigenetic markers (DNA methylation) between dogs and humans, proposed: human age = 16 × ln(dog age) + 31, valid from 1 year old onward. For puppies under 1 year, this calculator uses a linear approximation (human age ≈ 31 × age in years) that matches the logarithmic formula exactly at the one-year mark.
Examples
| Dog age | Equivalent human age |
|---|---|
| 1 year | 31 years |
| 2 years | ~42 years |
| 5 years | ~57 years |
| 10 years | ~68 years |
| 15 years | ~74 years |
Source: Wang, T. et al. (2020), "Quantitative translation of dog-to-human aging by conserved remodeling of the DNA methylome", Cell Systems.
Frequently asked questions
Does the formula apply to any breed?
The original study mainly used Labrador Retrievers. Very small or very large breeds may age at different rates, so treat this as a good estimate, not an exact value.
Why not just multiply by 7 anymore?
Because it greatly overestimates a young puppy's age and underestimates an older dog's — the real aging curve is logarithmic, not linear.
What about puppies under 1 year?
The logarithmic formula doesn't work well near zero, so we use a linear approximation that matches exactly 31 years at the dog's first birthday.