How Can You Calculate a Dog's Age in Human Years?

Do you want to know how old your dog is in human years? Here we'll tell you how to calculate it in a scientific way.
How Can You Calculate a Dog's Age in Human Years?

Last update: 21 May, 2022

If you have ever been told that to calculate a dog’s age in human years you only have to multiply the dog’s age by 7, then think again! A group of scientists have created a much more accurate formula, and they have even created an online calculator.

Here we’re going to tell you how they arrived at this formula and what advantages it has over the century-old 7-year relationship between humans and dogs. Don’t miss this article, because this goes far beyond simply knowing how old your dog would be if it were human.

How to calculate a dog’s age

How to calculate a dog's age.

There are many cases of owners who, having taken in an abandoned dog, have wondered how they can know how old the dog is. For this reason, before working out its human years, you need to know an approximate age for the dog.

The main factor to take into account is sexual maturity, which occurs around 6 months of age, more or less. Other signs also give us a clue:

  • Dentition: Provisional teeth erupt between 15 and 21 days old, and dentition occurs at approximately 6 months of age. The wearing down of the permanent teeth can be seen from the age of 3.
  • Gray hair: Dogs begin to grow gray hair on the eyebrows, chin, and cheekbones from 6 to 8 years of age. From that age on, it spreads to the rest of the body.
  • Joint wear and tear: Osteoarticular pathologies are more frequent in older animals, especially in large breeds.
  • Senses: Like any other aging animal, sight, smell and hearing become less acute as life progresses.
  • Other signs: Loss of memory, low activity, decline in coat quality, etc.

How to calculate the age of dogs in human years

Now that you know, or have estimated, your dog’s age, all that remains is to apply the necessary formula to estimate its age in human years. Researchers at the University of California (USA) have discovered that the relationship between a human’s age and a dog’s isn’t linear, as previously thought.

According to the study, a dog would reach maturity in its first year of life, but it would be equivalent to 30 human years.

In fact, dogs age faster at the beginning of their lives and this process slows down afterwards. Although the study was carried out using blood tests from Labrador Retriever pedigree dogs (which has the greatest similarity to human life expectancy), it can still give an approximate estimate for other breeds.

The formula for finding the equivalence between canine and human years

The aim of the study, in addition to finding the formula for calculating a dog’s age in human years, was to establish an equivalence between the life stages of both species.

The formula is as follows: if you want to know the age of a dog in human years, you must multiply its natural logarithm by 16 and add 31. Don’t worry if you aren’t any good at math, because they have created an online calculator.

This formula, as mentioned above, is able to find the equivalence in the aging process of both species. Apart from matching the average life expectancies of Labradors and humans (12 and 70 years, respectively), it also provides data such as the fact that a 7-week-old puppy is equivalent to a 9-month-old baby.

Applications of the formula

A Labrador.

Although this calculation will give an approximate answer, the truth is that its applications are very interesting. This technique, applied to find out the different vital periods of each breed, would give very interesting results regarding the aging of dogs.

These studies could find answers to why some dogs develop diseases at earlier ages than others, for example.

On the other hand, these calculators, called epigenetic clocks, let us calculate a biological age from DNA methylation levels. These hold promise as regards disease prevention, and also in advancing treatment for diseases associated with aging. However, when applied to certain issues in the human world, moral alarm bells are ringing.

In a world dominated by data traffic, the hands that monopolize these discoveries can use them for unethical purposes. There’s an open debate in this regard, with insurance and forensic science companies being accused of using this data for their own benefit.

Like everything else, each new discovery has its pros and cons. It’s the job of institutions and governments to use these studies to cure diseases and to prevent them from being used by insurance companies to decide how much to charge for their animal insurance policies.

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  • Wang, T., Ma, J., Hogan, A. N., Fong, S., Licon, K., Tsui, B., … & Ideker, T. (2020). Quantitative translation of dog-to-human aging by conserved remodeling of the DNA methylome. Cell systems11(2), 176-185.
  • Here’s a better way to convert dog years into human years. (s. f.). Science. Recuperado 18 de mayo de 2022, de https://www.science.org/content/article/here-s-better-way-convert-dog-years-human-years-scientists-say
  • Dupras, C., Beck, S., Rothstein, M. A., Berner, A., Saulnier, K. M., Pinkesz, M., … & Joly, Y. (2019). Potential (mis) use of epigenetic age estimators by private companies and public agencies: human rights law should provide ethical guidance. Environmental Epigenetics5(3), dvz018.