The old multiply-by-seven rule is too crude, because dogs mature very fast early and then age at a rate that depends on their size. A common veterinary guideline counts a medium dog first year as roughly 15 human years, the second as about 9 more, and each later year as 4 to 5, with small breeds aging slower and giant breeds faster. A free dog age calculator applies a size-adjusted model in your browser.
Free dog age calculator. Convert your dog age into human years using a realistic size-based formula. Find out how old your pup really is in human terms.
Open Dog Age Calculator → Free toolFree dog age calculator by breed size. Convert dog years to human years with a size adjusted model instead of the naive times seven rule.
Open Dog Age by Breed Size Calculator → Free toolFree cat age calculator. Convert your cat age into human years with a realistic feline formula. Discover how old your cat really is in human terms.
Open Cat Age Calculator →A one year old dog can already reproduce and has most of its adult body, which no seven year old human matches. The realistic pattern is front-loaded: enormous development in the first two years, then a steadier aging rate. That is why the guideline gives the first two years a large human-year value and each following year a smaller one.
Small breeds tend to be long-lived and age more slowly in later years, while giant breeds age fastest and have the shortest lifespans. A calculator that asks for your dog size class or breed applies the appropriate rate for the later years instead of one flat number for all dogs.
The same idea works for cats, with a different curve: fast maturation across the first two years and a steadier rate afterwards. A cat age calculator handles the feline version if your household is multi-species.
No. Early years count for far more, and later years for less, with the rate depending on the dog size.
On average yes. Small breeds commonly outlive giant breeds by several years, which the size-adjusted models reflect.
Around 28 to 29 under the common guideline: about 15 for year one, 9 for year two, and 4 to 5 for year three.