Understanding your dog’s age in human years is a common curiosity among pet owners. It’s only natural for us to want to know more about our furry friends’ ageing process, and see how they compare to us as they grow. For a long time, the idea that one dog year equals seven human years has been ingrained in our minds. In actual fact, the correlation between dog and human age is much more complex. In this blog, we’ll explore how to calculate your dog’s age in human years, and show you a handy chart to help estimate it.

Why the Seven-year Rule is a Myth

One of the most widespread myths is the ‘seven-year rule’, which assumes that every year of a dog’s life is equivalent to 7 human years. This formula might have come from an old statistic that dogs live to around 10, while people live to around 70. While multiplying by 7 might be a convenient rule of thumb, it oversimplifies the ageing process in dogs and has been proven to be inaccurate.

For one thing, it doesn’t account for differences in dog breed and size. The seven-year rule assumes that all dogs age at the same rate, which is not the case. Smaller breeds tend to live longer than larger ones, and many other factors are also at play.

Why Do Smaller Dogs Live Longer Than Larger Dogs?

For the most part throughout the animal kingdom, we can observe larger animals living for much longer than smaller ones. In dogs however, many people are convinced that smaller breeds tend to live longer than larger ones. Data is still being collected regarding how long different types of dogs live, and there is as yet no clear evidence for the theory that smaller dogs live longer than bigger dogs.

Having said this, following recent research from the University of Adelaide, a working theory was proposed, suggesting that larger dogs could be susceptible to cancer from a younger age. The theory suggested that the relationship between body size and lifespan in dogs may therefore be caused by an evolutionary lag in the body’s cancer defences. Bigger dogs have been more subject to selective breeding in recent years, making them more at risk of cancer.

Research from the Royal Veterinary College in 2022 has been able to help owners better understand the remaining life expectancy of their dogs. The study looked at 18 different breeds, and also identified which of these had the greatest and lowest life expectancies, highlighting wide differences amongst popular breeds.

Converting Dog Years To Human Years

So, we know that the size and breed of a dog are important factors when estimating their age in human years. But how do we calculate it?

There are a few different theories about how best to calculate a dog’s age in human years.

The American Veterinary Medical Association states that a one-year-old medium-sized dog is the equivalent of 15 years old in human years. Once they turn two, that’s equivalent to adding on roughly another nine years for a human. After that, each human year is around five years for a dog.

Other research has looked into changes in the DNA of dogs versus humans as they age. Following the results, the scientists involved put forward the following equation for figuring out dog age in human years: human age = 16 ln(dog_age) + 31. In maths, ‘ln’ or the log refers to the natural logarithm of a number. Only labrador retrievers were looked at in this study, however, so it may not be accurate for other breeds.

The American Kennel Club has proposed yet another idea. It suggested that the first two years of a small dog’s life is roughly the same as 12.5 human years, while it’s 10.5 for medium dogs and 9 for large dogs. Every additional year is then multiplied by a number between 4.3 and 13.4 (the exact number depends on the breed). The result is the dog’s age in human years.

How Old Is My Dog In Human Years

For most of us, these complicated mathematical equations don’t help to answer the question! Here’s an easy to use chart based on the UK Kennel Club’s equation to help you find your dog’s age in human years easily.

How Can You Help Your Dog To Live Longer?

Our dogs are part of the family, and the more time we get to spend together the better. Making sure that your pup leads a healthy lifestyle can help to ensure they reach a ripe old age. To make sure your dog leads a healthy life, you should:

• Have regular vet check-ups
• Keep up-to-date with vaccinations and essential treatments like flea control
• Regularly exercise your dog through walks and stimulating play
• Feed your dog a high quality diet and stick to portions advised by your vet to avoid obesity
• Pay attention to any behavioural changes, such as decreased energy levels or appetite. Spotting when something is wrong early on means you can work with your vet to address it as soon as possible

Wrapping Up

This topic has been a subject for discussion for many years, with many of us wondering exactly how dogs age compared to humans. While many theories and equations have been put forward, the truth is, there is no ‘hard and fast’ rule for determining this as of yet. Dogs and humans age differently, so it’s difficult to give an exact answer as to how many human years are equivalent to a single dog year. Despite this, we hope you’ve gleaned an insight into how your dog’s age might compare with your own.