How Old is My Dog? Understanding the Seven Year Theory


We have all heard it before. In order to determine the age of your dog in “human years” just multiply their age times seven.

Is this really the most accurate way to calculate your dog’s age?

The truth is, the seven years theory is really just an average of how dogs age in comparison to humans. However, at any point in their lives they could be aging slower, or faster, than 7 years per 1 calendar year.

For example, it is common knowledge among animal professionals that dogs age must faster in their early years of life, and slower in their later years. Additionally, size and breed directly affect the speed of your dog’s aging.

Photo Courtesy of

Photo Courtesy of

Notice, according to this chart, smaller breeds tend to mature faster in early years than larger breeds. Then, the larger breeds start to approach senior age more rapidly.

According to the above chart, Rooney is about 36 years old (he is 4.5 years old right now and weighs 30 pounds). However, if we use the 7 years theory, Rooney would be 31.5 years old (4.5 times 7). Since he is still young, the seven years theory is underestimating his age, because he is actually aging more rapidly at this stage in his life. However, when Rooney turns 8, according the chart he will be 51, and according to the 7 years theory he is be 56. Meaning, now that he is in his older years, the seven years theory is overestimating his age.

If its wrong, then who said it first?

After doing some research, I couldn’t find the answer.

It seems that no one is claiming to own this theory in any particular way, but that the first and only evidence was found in a math text book that asked children to calculate a dog’s age using 7:1 ratios (BBC).

No matter where it came from, it is one of the most misunderstood myths about dogs.

Please tell me, according to the chart, how old is your dog?

I want to thank Sugar the Golden Retriever and Nola the Dachshund for hosting this Blog Hop.


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12 Comment

  1. Reply
    January 4, 2015 at 9:57 am

    The Peeps say we need a reverse chart. Pout in their age and get their age in dog years. That ought to make them smile.
    Kismet recently posted…Happy Snow YearMy Profile

    1. Reply
      January 21, 2015 at 7:22 pm

      Lol..that would be awesome Kismet!

  2. Reply
    January 4, 2015 at 10:09 am

    As planned, my boys are all aging similarly- Wilhelm is 44, Brychwyn is 34 and Huxley is 29. I enjoying watching them grow old together and, of course, stay constantly young at heart.
    Bethany recently posted…Black & White Sunday: The Sea Casts Its Spell on Three Dogs, A Cat & A CockatooMy Profile

    1. Reply
      January 21, 2015 at 7:23 pm

      Bethany, I love how dogs remain so young at heart!

  3. All three of my dogs age differently. My dog Lilah started showing gray around her muzzle when she was only four years old. Part of that is because she’s black, and the white shows really well. I also like to think it’s hereditary; I started turning gray in my twenties! 😉
    –Wags (and purrs) from Life with Dogs and Cats.
    Susan and the gang from Life with Dogs and Cats recently posted…Meow Parlour: Cat Cafe in the CityMy Profile

    1. Reply
      January 21, 2015 at 7:24 pm

      I started going gray in my 20’s too! I blame grad school! Lol

  4. Reply
    Golden Woofs: Sugar
    January 4, 2015 at 1:57 pm

    Totally understand the age chart. I did a research years ago. Many can’t believe that Sugar is 13 and acts like a puppy. Golden Woofs

    1. Reply
      January 21, 2015 at 7:24 pm

      Sugar is so sweet! I can’t wait to see her at BlogPaws!

  5. Reply
    January 4, 2015 at 4:25 pm

    Well, according to the above chart, my 14.5 year old dog is 74, but using the 7 year theory, she is 101. It doesn’t really matter, I know she is very old because I see her slowing down, takes shorter walks. doesn’t play as much and sleeps most of the day. Sounds like me actually!
    Barb recently posted…You are the best – thank youMy Profile

    1. Reply
      January 21, 2015 at 7:25 pm

      Lol…sounds like me too!

  6. Reply
    Groovy Goldendoodles
    January 7, 2015 at 4:55 pm

    Very interesting. According to the chart Harley is now 42.

    1. Reply
      January 21, 2015 at 7:25 pm

      Still young 🙂

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