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How To Calculate Your Dog's Age (Don't Just Multiply By 7!)

Dogs do have much shorter life spans than we humans do. In an attempt to gauge our pet's stage in life in a way we can relate to, we often use the popular myth of multiplying their age by seven.

Small Dogs and Large Dogs

One problem with the formula is that it doesn't consider differences in size or breed. In general, smaller dogs live longer than large ones, but reach adulthood sooner.

It's fairly common for small dogs to live past sixteen years, so are they really the "age equivalent" of a 112 year old human?

On the other hand, for very large dogs to live to sixteen is as rare as humans living to 112, and so the formula may give a closer approximation in that case.

Reproductive Age

Dogs also reach reproductive age sooner than humans do.

By eighteen months old, most dogs are full grown and capable of reproducing, but using the old formula, an eighteen-month-old dog would only be equivalent to a ten-year-old human, and they're still far from adulthood.

So is there a better way to calculate a dog's age in "human years"?

It can be useful to understand what health problems may occur as they age, and when to expect certain changes in their bodies and behaviors.


There isn't one formula that works for all dogs, but there are several good calculators online that factor in breed or size. Here are a few links: Purina and WebMD.

Your veterinarian can also provide advice to help your dog live a long and healthy life.

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