Dog Age (Epigenetic Formula) Calculator

About this calculator

The old “multiply by seven” rule for dog years is a myth. The formula used here — human age = 16 × ln(dog age) + 31 — comes from a 2020 study by researchers at UC San Diego who compared DNA methylation patterns (chemical markers on DNA that shift predictably with age) between Labrador retrievers and humans, published in the journal Cell Systems. Because it is based on a natural logarithm, it captures how dogs age extremely fast in their first couple of years — a one-year-old dog maps to roughly a 31-year-old human — and then the aging rate slows dramatically compared to the crude linear 7x multiplier.

Veterinarians and pet owners use an epigenetic-style estimate like this to reason more accurately about a dog’s life stage, since a 2-year-old dog is already biologically closer to a human in their late 20s or early 30s, not 14 as the old rule implied, while a senior dog’s aging pace evens out later in life much as a human’s does.

Enter your dog’s age and this calculator applies the logarithmic formula directly to estimate the equivalent human age.