How Dog and Cat Age Charts Work
Size, early-life credits, and why ×7 misleads
How Dog and Cat Age Charts Work
Educational pet aging charts front-load human-year credits into the first two years. Here’s the arithmetic our dog and cat age calculators use—and what they deliberately leave out.
Search results still push “multiply by seven.” That mnemonic ignores the rapid maturation of puppies and kittens. Size-based charts improve on ×7 without pretending to be a clinical geriatric score.
Dogs: size changes the thereafter increment
After year two, small dogs often add about four human years per calendar year, medium five, large six, and giant seven—while giant year-one credits may start lower than the 15 used for smaller dogs.
Cats: a single educational chart
A common cat chart uses 15 + 9 + four human years for each year after two. Lifestyle still matters enormously for real longevity.