Calculate Dogs’ Ages

Scientists Found Better Way to Calculate Dogs’ Ages, 1 Dog Year ≠ 7 Human Years

Posted by Feng Jiang on

Do you know the real age of your puppy? For many years, we have been told 1 dog year equals 7 human years. But according to a new study released in July 2020, scientists find out a new way to calculate dogs’ ages, which proves the 1:7 ratios to be an inaccurate measure of age. In this article, Happy & Polly will show you this new way to calculate a dog’s ages.

dog age

Dog Age Research

The research was done by scientists of the University of California San Diego (UCSD) School of Medicine. They worked with genome experts to devise a more accurate formula to calculate a dog’s age. This formula is based on the chemical changes in the DNA.

To learn more about dogs’ aging process, scientists gathered and analyzed blood samples of 105 Labrador retrievers, with different ages from a few weeks to 16 years old. They sequenced the genomes of the Labradors to tune “DNA methylation”, which is a process that many species undergo as they age.

They also developed a new molecular tool called the “epigenetic clock”. Using this tool, they can drill into the rate of molecular changes in dog’s DNA to learn the patterns of change in chemical markers on the DNA of aging.

DNA methylation

According to the research, during the course of life, human and dog DNA doesn't change much, but chemical marks on the DNA do. We learn from one researcher of this team that the epigenetic changes provide clues to a genome’s age – similar to wrinkles on a person’s face which provides clues to their age.

How to Calculate Dog Years?

Although dogs share the same environment as human beings and also follow similar developmental trajectories, scientists found that on a molecular level, their aging is much more complicated. In dogs' first year of life, Canine epigenetic clock ticks much faster than the human one. But as years pass, the clock rate slows down later in life.

According to this study, the equation to calculate a dog’s age in human years is: A dog's human age = 16 * ln(age in dog years) + 31, which means you multiply the natural log of a dog's age by 16, then add 31.

If you don’t understand the equation, you can refer to the below graph depicting the new aging formula for dogs.

graph of the new aging formula

From the above equation and graph, we can learn that: age of an 8-week-old puppy = that of a 9-month-old baby. However, a 1-year old puppy is like a 30-year old human, while a 4-year old dog is similar to a 52-year-old human. They are really much older than we thought they were.

However, these data were only based on Labrador retrievers. Though dogs live about 12 years on the average, some breeds may live longer. More tests on other breeds will be needed to prove this clock applies to all breeds.

We hope this article can help you better learn your dog. If you enjoyed it and would like to see more news, do not hesitate to visit Happy & Polly website on

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