How Old Your Dog Actually Is In Human Years, According To Updated Scientific Equation

Written on Feb 17, 2026

dogs age human years updated scientific equation acob Lund | Shutterstock
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We've all heard it a million times: One human year is equal to seven years for a dog. But new scientific research has an updated scientific equation to determine how old your dog actually is in human years.

The bad news is that it shows that our dogs are all likely much older than we thought. And it all comes down to a newly discovered part of how puppies age.

How to determine your dog's actual age in human years, according to a new scientific equation.

woman holding her dog ages faster than originally thought updated scientific equation DimaBerlin | Shutterstock

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The seven years rule has been the conventional wisdom for decades, but scientists at the University of California, San Diego have discovered that it's actually quite inaccurate.

To analyze this, researchers looked at a process called methylation, which impacts DNA as an organism ages. Methylation markers don't change the genes themselves, but they do change the aging patterns of an organism over time. And in analyzing dogs, the scientists found that we'd been viewing dogs' aging all wrong.

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Puppies actually age much faster than previously realized, so adult dogs are actually much older.

The methylation markers revealed that puppies actually age very rapidly, so much so that a one-year-old puppy is actually more like a 30-year-old in human years, not a 7-year-old. Yes, your dog, barely out of his puppy stage, should actually have a full-time job and a 401 (k).

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Lead researcher Trey Ideker, a professor of genetics at the UCSD School of Medicine, told NBC News that in retrospect, this should have been obvious to scientists all along. "It didn’t make any sense that the equivalent of a 7-year-old human would be able to have puppies," he said. Fair enough.

dog having a birthday party RuthBlack | Getty Images | Canva Pro

The good news is that as fast as a puppy's aging goes, it slows way down as a dog gets older, so it's not like your pupper goes from 30 to 83 in the span of a year or two. But it does mean that our dogs are much older in human years than we thought.

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A 5-year-old dog, for instance, isn't the usually assumed 35 in human years. He's actually in his golden years, having just turned a whopping 60. Old enough for the AARP and everything!

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Scientists have created a new equation to get a dog's human age.

The other bad news is that the new way of calculating a dog's age in human years isn't nearly as straightforward as just multiplying his age by seven. 

To do it, you have to use something called a natural logarithm, and as the holder of a liberal arts degree, I don't even know what that is, let alone how to explain it to you.

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However, your calculator does have a button for it, labeled 'ln' for whatever reason. The equation is: 16 ln(dog age) + 31 = human age. So type in your dog's age and hit the 'ln' button; then multiply that result by 16, and add 31. That's your dog-human age.

man with his dog Nikola Stojadinovic | Getty Images Signature | Canva Pro

So a 5-year-old dog is about 57 years old, if I did the calculation correctly, which I absolutely cannot and will not promise is the case. Regardless, it's much older than we thought: The UCSD scientists calculate that in human years, puppies age 9 months in their first 8 weeks; 1-12 years in the first 2-6 months; 12-25 years from 6 months to 2 years; and 25-50 years in years 2 through 7.

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But before you get too sad, the scientists also found that dogs' aging slows way down after seven years, only adding about two human years between ages 7 and 8. So don't worry, your dog isn't going to suddenly be 94 one day.

In fact, the longest-lived dog in history, an Australian Shepherd named Bluey, who lived to be an astonishing 29 years, only lived to 85 in the new equation. My 90-year-old aunt has shoes older than that. That's nothing!

RELATED: Research Proves That Your Relationship With Your Dog Is More Satisfying Than Your Relationship With Most Humans

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John Sundholm is a writer, editor, and video personality with 20 years of experience in media and entertainment. He covers culture, mental health, and human interest topics.

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