What this page does
These age tools share one size chart and answer different questions: calendar age, human years, the reverse conversion, senior start, and countdown.
Calendar age is the time from the date you enter to the date on the page. The human-year figure is not a logarithm and not “times seven.” Year one is 15 human years (12 for a giant). Year two ends at 24 (22 for a giant). Each later year adds 4 small, 5 medium, 6 large, or 7 giant. A fraction of a year is proportional. Senior starts at 11, 9, 7, or 6 years.
The same medium dog at 5 dog years is 39 human years on this chart. A giant dog uses 12, then 22, then 7 human years per later year, so the same 5 dog years are not 39.
How the estimate works
Press Calculate before reading the panel. A half-typed date is not an age. If you choose a breed, the size bucket changes to that breed’s row and the human-year line changes with it. The written example on this page is the default before a breed is chosen.
Size is a bucket you choose, not a weigh-in. The page uses one “today” when it is first drawn, then the date on your device.
A human-year number does not say how healthy a dog is, and it does not date a disease.
Limits
Birth dates in the future are rejected. February 29 anniversaries move to the 28th when the year has no 29th.
Breed guides are separate pages for forty well-known names. They are not extra copies of this calculator. A Labrador guide uses the large line. The 39 human years in the medium example stay on the general age tools.
Why not seven dog years for every human year?
Questions
Because the first two years do more of the aging on this chart than the later ones, and a giant breed does not share the small-dog line. Five medium years are 39 human years here, not 35.