Frequently Asked Questions
Why not just multiply by 7?
The "×7" rule assumes pets age at a constant rate every year, which isn't how it actually works — both dogs and cats mature extremely fast in their first year or two, then age more slowly afterward. A 1-year-old dog is already roughly equivalent to a 31-year-old human under the accurate formula, not 7.
Where does the dog formula come from?
A 2019 study from UC San Diego (published in Cell Systems) compared DNA methylation patterns — a kind of biological aging clock — between dogs and humans, and found the relationship follows a logarithmic curve rather than a straight line. That's the formula used here.
Does breed or size affect a dog's aging rate?
Yes, in reality larger dog breeds tend to age faster in their later years than small breeds — this calculator uses the general formula from the study, which doesn't account for breed size, so treat the result as a solid general estimate rather than breed-specific.
Is the cat formula backed by the same kind of study?
The cat chart used here is the widely adopted, improved standard used by veterinary and animal-welfare sources — reflecting the same fast-early-then-slower aging pattern as the dog study, even though it comes from broader veterinary consensus rather than one specific genomic paper.