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How Old Is My Dog?

Calculating Your Dog's Age in "Human Years"

By Mary Kearl. February 25, 2013 | See Comments

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How Old Is My Dog?

How do dog years correspond to people years? The rule of taking your dog’s age and multiplying by seven doesn't always work. Learn how to calculate your dog's age here.

As pet parents, we want the best for our dogs, especially when it comes to helping them age in good health—so that their golden years may truly be golden. Part of that is having an understanding of how old your dog is in terms of their own lifespan. What stage of life a dog is in will affect the type and level of care they need.

Dog Years vs. Human Years

Just how do dog years correspond to our own? Though it’s treated as common knowledge, the rule of taking your dog’s age and multiplying it by seven isn’t quite accurate. For starters, it doesn’t take into account the range of canine breeds and sizes or factor in the difference in how early in life dogs begin reproducing compared with at what point in our lives we humans tend to hit puberty. Research indicates that before age 1, the aging process in dogs can be as much as 20 times faster than that of humans. Later in life this ratio is about 5:1.

Citing The Journals of Gerontology, The Wall Street Journal reported that by age 1 a Miniature Poodle is about 10.9 in human years, whereas a Great Dane is 26.8 in human years.

Instead of multiplying your pet’s age by seven, some suggest following this rule: for small-breed dogs (10-15 pounds), which tend to live longer, multiply the animal’s age by six to find the human equivalent. For larger dogs, with generally shorter life expectancies than smaller canines, multiply the age by eight.

How to Tell If a Dog Is a Senior

There is no clinically defined age for the start of the last phase of a dog’s life, but a good rule of thumb is to think of this stage’s duration as equivalent in years to the last quarter of your dog’s lifespan. So for larger dogs, that will usually be from age 7 to 10 and for smaller pooches that could be from about 14 to 18. Check this handy dog lifespan by breed chart to see when your dog may enter their senior years. Generally, when your dog hits this stage in life, it’s recommended to start offering a senior dog diet.

Signs of Aging Can Include:

  • White or gray hair around the mouth and nose
  • Loss of sheen or gloss of the coat
  • Thinning fur
  • Taking more time to do things, like waking up and getting out of bed
  • A drop in energy level and interest in play
  • Difficulty seeing and hearing, which may make your pet less responsive to your attention or commands
  • Cloudy eyes, which may indicate vision problems
  • Weight change
  • Troubles getting on and off furniture or in and out of cars
  • Irritability around children and other dogs
  • Having to go potty more often, including not being able to hold it through the night
  • Incontinence
  • Lower tolerance to extreme temperatures and weather
  • Dental disease and bad breath
  • Aches and pains due to aging-related arthritis
  • Skin growths 

Healthy, Happy Golden Years

In healthy dogs, these changes should be gradual. Senior dogs generally have stable habits, so any jarring deviation from the routine--be it related to behavior, activity, weight, diet, or elimination--could signal a health issue that needs immediate attention from a vet. It’s recommended to take older dogs to the vet twice a year. Regular tooth brushing is advised to combat aging-related dental issues.

Common aging-related health issues in dogs include those related to the intestines, kidneys, liver, prostate, brain and joints, as well as breast cancer, testicular cancer, arthritis and diabetes.

Seek Medical Care If You Observe:

  • Incontinence
  • Lumps
  • Constipation or diarrhea
  • Difficulty breathing
  • Coughing
  • Weakness
  • Weight fluctuation
  • Out of the ordinary urinating or drinking
  • Stiffness or limping
  • More barking, whining, or growling
  • An increase in aggression
  • Drastic change in behavior
  • Unusual discharge of the eyes or ears
More on Senior Dog Care

10 Questions for Your Senior Dog's Veterinarian
The Best Senior Dog Supplies
Incontinence in Dogs

This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian with respect to your pet. It has, however, been verified by a licensed veterinarian for accuracy.

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Dog Age at a glance

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  • 1There’s no one-size-fits-all rule of thumb for calculating a dog’s age in equivalent human years.
  • 2For smaller dogs, multiply the animal’s age by six; larger dogs by eight.
  • 3Dogs become seniors in the last quarter of their lifespan.