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Dog Age Calculator (Dog Years to Human Years)

So, how old is your dog? Is she still a puppy, or should she be considered a senior? Many people try to relate their dog's age to human years to better answer these questions. But what many people do is simply multiply their dogs calandar age by 7. This is not only a bad assumption, it can be very inaccurate. No basis for this simple math relationship to a dogs age exists. One source I found was that it first appeared in a math book in the 1980s as a general assumption for converting a dogs age to human years. However, I remember using that calculation when I was just a puppy myself, and that was quite a bit before the 1980s!

This page has three different dog age calculators, with an explanation for what is being used in the calculation. Each successive calculation will become more representative of your dog's true age, as it relates to human lifespans. Try each one for your dog, comparing the results. Let's get started!

Dogs Age Faster During Their Formative Years

This actually makes a lot of sense. Under the old seven years to one year, your dog would be equivalent to 7 years old on her first birthday! Yet almost all of the growing has already occurred. How many 7 year old children are almost adult size?

This calculator recognizes this quicker aging, allowing the age to rise to 24 years in the first two years, then adding 4 years for every year thereafter. The calculation will simulate the curve shown below. If you are like me, and need to see the curve a bit bigger, simply click on the image and a larger chart will open in a new window.

Dogs age faster earlier in life

What type of dog do you have?

How old is your dog?

Your Dog’s Size Affects Her Relative Aging

For the first two years, small, medium, and large dogs age quicker than later, achieving a relative age of 24 in those first two years. Giant dogs, because of their slower development, are only about 18 human years in those same two years. However, after those two years, the larger the dog breed, the faster it will typically age. So, that giant dog not only catches the small dog quickly, she will then age at a much more rapid rate than the smaller dogs.

It turns out that the small dog indeed ages at around the 4 years per calandar year discussed above, but the giant dog ages almost twice as fast! See the chart below, and again, if you want a bigger chart, simply click on the image.

Dog aging varies with size

What type of dog do you have?

How old is your dog?

Each Dog Breed Ages at Their Own Rate

There is a problem with both dog age calculators shown above.

They both place all dog breeds into one or more general categories. In reality, longevity is breed specific! For example, the Tibetan Mastiff, a giant breed using the second calculation, has an average lifespan of 12.5 years. However, the English Toy Spaniel is a small dog breed using that calculation, yet it has an average lifespan of 11 years.

Putting 12 Years for these two breeds into the dog age calculators above, we get equal ages in the first calculator, and the following results for calculator 2:

  • Your dog is a giant dog. So, in human years, your Tibetan Mastiff is 94 years old.
  • Your dog is a small dog. So, in human years, your English Toy Spaniel is 64 years old.

So the Tibetan Mastiff, while not yet reaching its life expectancy, is 30 years older than the English Toy Spaniel, who is actually 1 year beyond its average life expectancy!

To get the most accurate determination of your dog’s age, the dog age calculator below uses actual average lifespans for each breed. As a further enhancement, you can enter a nation, and your dogs age will be compared to the average human life expectency in that nation. The chart below is just a representation of that calculator, using 6 random dog breeds (OK, maybe not so random, since I included the two discussed in this section, and included the dalmatian, which I happen to have a 16 year old. But the other three are random, promise!)

Each dog breed ages at its own rate

What type of dog do you have?

How old is your dog?

What nation are you from?

Visitor comments

So, were you surprised with the results? Any questions on how each of the dog age calculators actually work? And How Old Is Your Dog? Comments are welcome.

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