Dog age calculator
The "multiply by 7" rule was never based on science. Dogs race through their first year, then age more slowly.
How this works
In 2020, researchers at UC San Diego compared DNA methylation patterns ("epigenetic clocks") in Labrador Retrievers and humans. They proposed human age = 16 × ln(dog age) + 31. By that formula a 1-year-old dog is roughly 31 in human terms, and a 4-year-old about 53.
Two honest caveats. The study used Labradors only, and size matters: giant breeds tend to age faster and live shorter lives than small breeds. Treat the number as a conversation starter, not a diagnosis. Most vets consider dogs "senior" from around 7 years for large breeds and 8–10 for small ones.
Source: Wang T. et al. (2020), "Quantitative Translation of Dog-to-Human Aging by Conserved Remodeling of the DNA Methylome", Cell Systems 11(2).