Dog Age Calculator
Convert your dog's age into human years using a size-adjusted formula.
Assumptions used in this calculation
- Size-adjusted aging: Larger dogs age faster in later years than small dogs, this uses commonly cited veterinary approximations, not an exact biological formula.
About this calculator
The old 'multiply by 7' rule for dog years is well known but badly wrong, since dogs mature to adulthood within about two years while humans take roughly eighteen, and large breeds age faster in their later years than small breeds do. This calculator uses commonly cited veterinary aging curves instead: the first year counts as roughly 15 human years, the second adds about 9 more, and each year after that adds somewhere between 4 and 8 years depending on your dog's size category, since bigger dogs' later years compress into a shorter remaining lifespan. Enter your dog's age and size, and it applies that non-linear, size-adjusted scaling instead of the flat multiplier, giving a much more realistic sense of your dog's life stage, whether they're still developmentally a puppy, in their prime, or entering their senior years, than the oversimplified ×7 shortcut most people still reach for.
Worked example
5-year-old medium dog
Result: ≈ 36 human years
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