How to Convert Dog Years to Human Years

The typical lifespan of a dog is 12 to 14 years depending on the size, breed, and overall health of your pet. In the old method of converting a dog's age to a human age, you simply counted 7 human years for every 1 dog year. That is, you multiplied the dog's age by 7. However, this method fails to account for several things. One is that small breed dogs have longer lifespans than large breed dogs. Another is that dogs reach reproductive maturity much more quickly than humans, as compared to the total lifespan. Each of the first few years of a dogs life count for much more than 7 human years.

To account for these facts, there is a revised way of converting dog years to human years. You can use the converter calculator at left to compute your dog's age in human years, or follow the step-by-step guide below.


One Year Old Dogs

First determine the adult weight of your dog. If your dog weighs less than 30 lbs as an adult (under 13.6 kg), then the first year is equivalent to 15 human years. If your dog weighs between 30 and 80 lbs as an adult (13.6 to 36.3 kg), then the first year is equal to 14 human years. For dogs that weigh more than 80 lbs as adults (over 36.3 kg), the first year is equal to 13 human years. Small breeds reach sexual maturity slightly faster than large breeds.

Two Year Old Dogs

For dogs that weigh under 30 lbs, two dog years is equal to 24 human years. For dogs that weigh between 30 and 80lbs, two years equals 23 human years. For dogs that weigh more than 80 lbs, two years is equivalent to 22 human years.

Dogs Older Than Two Years

For dogs that weigh less than 30 lbs, count 4 human years for every 1 dog year after the first two years. For example, 3 dog years = 24 + 4 = 28 human years, 4 dog years = 28 + 4 = 32 human years, etc.

For dogs that weigh between 30 and 80 lbs, count 5 human years for every 1 dog year after the first two years. For example, 3 dog years = 23 + 5 = 28 human years, 4 dog years = 28 + 5 = 33 human years, etc.

For dogs that weigh more than 80 lbs, count 6 human years for every 1 dog year after the first two years. For example, 3 dog years = 22 + 6 = 28 human years, 4 dog years = 28 + 6 = 34 human years, etc.

Example Calculations

Fifi is 8 years old and has reached an adult weight of 16 pounds. Her age in human years is

24 + 4 + 4 + 4 + 4 + 4 + 4 = 48.

Rover is 10 years old and has reached an adult weight of 95 pounds. His age in human years is

22 + 6 + 6 + 6 + 6 + 6 + 6 + 6 + 6 = 70.

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