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We have all heard the myth that one human year equals seven dog years. However, a one-year-old dog is more mature than a seven-year-old child. In fact, a one-year-old dog is similar to a fifteen-year-old human. Find out how to calculate your dog’s age.
Pet dogs are increasingly treated like “little humans. Just as we tend to categorize ourselves by our age, so we often like to compare our pets to their human age equivalent. There’s a logical way of approaching this, and it starts by ignoring the method that most people have heard of…
1. Forget the old myth that one human year equals seven dog years
This is the traditional method of calculating a dog’s “human” age. It makes the assumption that since dogs have shorter lives, their life flashes past at a rate that’s simply speeded up on a pro rata basis compared to our own. So given that the average human life expectancy is around eighty, and an average dog might live for eleven years or so, this works out at around seven dog years equal one human year.
While this comparison has been in use for fifty years or more, and it may be broadly correct for an “average” older dog, there are aspects which are plainly wrong.
- A one-year-old dog is far more adult-like than a seven-year-old child
- Dogs often live over fifteen years of age, while it’s rare for humans to live over 105.
- Dogs have been known to live well over the age of twenty (“140 dog years”), with the oldest ever dog lived to be 29 (“203 dog years”), while the oldest human ever only lived to be 122 years of age
2. Speed up the first two years then slow down
Dogs grow far more rapidly than humans from birth to adulthood: a one-year-old dog is similar to a fifteen-year-old human, and a two-year-old dog is equivalent to a twenty-four-year-old human. After that, dog’s age something like three to five “dog years” per human year, depending on other factors. This wide bracket of “three to five years” is an effective way of dealing with the anomalies of the oldest dogs living far longer than the older humans.
So, using this principle, the twenty-nine-year-old “oldest dog” would be 24 plus (3 x 27 = 81) = 105 years old, which is far more reasonable.
However this method doesn’t deal effectively with the fact that some dogs – like Great Danes – may die of old-age-related problems at just seven or eight years of age, so a further modification is needed.
3. Take dog type and breed into account
Age expectancy in dogs is strongly related to the size of the animal. Giant breeds such as Great Danes or St Bernards age more rapidly, often only living to six or seven years of age. In contrast, small breeds like Miniature Poodles commonly live past fifteen years of age, and they’re more likely to survive into their twenties. Middle-sized dogs tend to fit into the middle of these extremes, living till twelve to fifteen years. Pedigree dogs tend to live shorter lives than cross-breeds but there are exceptions to this rule. The Mongolian Bankhar is a large livestock guardian breed that lives until their late teens/early twenties despite living in harsh traditional conditions, confounding the principle of big-dogs-dying-younger.
It’s difficult to be specific about the impact of breed on lifespan, but the Kennel Club does run regular surveys which can act as a broad guide to expectations for particular breeds.
The most detailed and up to date information to include cross-breeds is contained in a recent survey which looked at the records of over 100000 dogs in England, focusing on over 5,000 deaths. The overall median longevity was 12 years, the longest-lived breeds were the Miniature poodle, Bearded collie, Border collie and Miniature dachshund, while the shortest- lived were the Dogue de Bordeaux and Great Dane. The survey found that longevity in crossbred dogs exceeded purebred dogs by an average of 1.2 years and that increasing body weight was negatively correlated with longevity.
If you have a cross-bred dog, you can often just guess their breed background with some degree of accuracy, but if you want to take a scientific approach, you can send off a cheek swab from your pet to have basic genetic analysis carried out. This will give you the closest possible estimation of your dog’s breed mix, and you can go on from there to investigate their expected age span.
4. Use an online computerized age calculator
It can be fiddly to work out your pet’s early life, plus so many years per so many calendar years depending on factors like breed and size. Thankfully, computer boffins are there to make the job easier for you. There are several free online dog age calculators which you can use to work out approximately how old your dog is in human years. Enter the appropriate details, click on the button, and you’ll be given the answer.
Be warned, however, this is really just a bit of fun. Just as with humans, calculating longevity is an inexact science: there are some individuals who have much shorter lives than expected, and there are those lucky few who live on and on and on. Expectations based on breed, size, and type might be right for the “average” dog, but very few owners would agree that their own dog is average in any way at all. Every pooch is special, with its very own special allocation of years on this planet.
if you prefer a video, check out on how to know the exact age of our dog?