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Dog Age Calculator

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To better understand your best friend’s age, our dog age calculator converts your dog’s years into equivalent human years. Simply enter your dog’s size or its specific breed and current age to get your custom result!

How does the calculator work?

Our dog age calculator takes into account the fact that dogs mature faster than humans.

  • The first year of a dog’s life is similar to the first 15 years of a human’s.
  • The second year of a dog’s life is about 24 human years.

After that, we compare the average lifespan of a dog to the average human’s lifespan, which is currently about 76 years.

dog with birthday hat and cupcake

Is a dog year 7 human years?

While the traditional formula people may use to determine a dog’s human age is multiplying their age by seven, this isn’t accurate.

It probably started because a typical human age was around 70, and a dog’s lifespan was around ten years. This doesn’t consider that dog breeds have different life expectancies. It also doesn’t acknowledge the quick maturity rate in a dog versus a human.

How does size affect a dog’s life expectancy?

It’s still not understood why larger dogs tend to age faster, but it’s thought that this may be due to their quick growth, making them more susceptible to diseases. You can see how this works in the table below:

Dog life expectancy by size

Small DogsMedium DogsLarge DogsGiant Dogs
Weight0-20 lbs21-50 lbs51-99 lbs100+ lbs
Life Expectancy10-15 yrs10-13 yrs10-12 yrs8-10 yrs

These sizes are less accurate than knowing your specific breed’s life expectancy, but they are a good approximation.

blonde dog names

How to calculate a dog’s age

According to the American Veterinary Medical Association:

  • The first year of a small to large-sized dog’s life equals approximately 15 years of a human’s life.
  • The second year of a dog’s life equals about nine years for a human (making 24 years in total).
  • After that, every human year equals approximately four or five years for a dog, depending on size or breed.

Remember that, like humans, each dog’s lifespan will vary based on genetic, environmental, and other health factors. These numbers are just a guide to finding some typical age ranges.

How to calculate the age of a mixed-breed dog

The fastest way to calculate a mixed-breed dog’s age is to calculate by dog size. For a more specific calculation, you can average the lifespan of its parent breeds and use that to understand how its life expectancy may vary from the standard.

dog age calculator table infographic
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