How old is a 13 year old bulldog in human years
Dog Years Calculator
Quick navigation:
- Using the dog years calculator
- How do dog years work?
- Dog years to human years formula
- Dog age chart
- Limitations of the dog age calculator
- The myth of multiplying dog age by seven to get the human age
- How many dog years are in a human year?
Using the dog years calculator
This dog age calculator makes it easy to answer the question how old is my dog in human years? If you know your dog's age, just enter it as either a number of years or months. If you don't know the age, but know the dog's birth date, enter it instead and our tool will calculate the dog age in calendar years for you. Finally click "Calculate Human Years".
The output of the calculator is the number of human years, and the equivalent human age in years and months. The tool converts dog years in human years using the formula below.
How do dog years work?
The idea of 'dog years' and 'human years' is to more easily assess what stage of life your dog is: puppy, junior, adult, mature, senior, or geriatric. While different animal associations and veterinary associations might have charts and guidelines for that, for regular people it is much easier to understand when the dog's age is converted to the age of a human in an equivalent phase of physical development. For example, 9 years in dog years are equal to 66 human years, meaning that a 9-year old dog is roughly equivalent to a 66-year old person. Some use the term 'dog years' to mean 'human age equivalent years' while the scientific literature prefers the term 'human years' as more accurate.
The application of this idea is mainly in veterinary work, but it can also help dog owners appreciate the stage of life their pet is in, the physical difficulties that may entail, and so on. Both human and animal life spans have increased over time due to superior care and the availability of more economic resources which can be dedicated to animal healthcare. Continued improvements are unlikely with the current state of medical science, but should they become a reality, we would need to change the way we convert dog years to human years.
Dog years to human years formula
The dog age to human age conversion formula we use in this dog years calculator is based on research by Wang et al. (2020) [1]. Its derivation comes from the comparison of human DNA methylation changes with those of dogs. Methylation is experienced by mammalian genomes as they age and can serve as a sort of epigenetic clock. It is linked with life spans of various species and hence can serve as a model of aging.
In the equation above, HumanAge is the age equivalent of a human in years whereas DogAge is the age of the dog measured in calendar years. ln is the natural logarithm function. For example, a 12 year old dog will be nearly 71 in human years.
Dog age chart
The dog years chart below presents the equivalent human age for a given dog age. Since it was calculated using this dog years to human years calculator, it is subject to the same limitations as the tool itself.
The chart can be used to tell how old is 4 in dog years, or the reverse, e.g. what is 9 years in dog years.
Limitations of the dog age calculator
Since the research used to construct this tool was carried on 104 Labrador retrievers spanning a 16-year age range, it may have lower validity for other dog breeds. It should be used with caution for breeds that exhibit a typical lifespan much different than that of Labrador retrievers. E.g. it might work well for a Boxer, a Pitbull or a German Shepherd, but it will probably slightly overestimate the human equivalent age of a Yorkie, a Labradoodle, a Maltipoo, a Cockapoo, a Shetland sheepdog, or a Jack Russell.
Additionally, the dog years equation does not support dog age less than approximately 1.8 months. For this reason a dog age below 1.8 months is calculated as 0.3 human years, which should serve as a rough approximation.
The myth of multiplying dog age by seven to get the human age
For many years the standard advice was that in order to get the human years equivalent, one needs to simply multiply the dog age by seven. So a two year old dog would have a human age equivalent to a 14-yeard old adolescent. However, this advice was never scientifically backed. For example, most dogs would reach sexual maturity between six and twelve months old, well before the two-year mark suggested by this simple approach.
Some believe that this basic advice was given to dog owners so they would remember they need to bring in their companions for a regular check up at the veterinarian office at least one a year. If one dog year is equal to seven human years, that actually sounds like conservative advice.
How many dog years are in a human year?
Understanding the non-linear monotonic relationship between dog years and human years means asking questions like how many dog years are in a human year is meaningless. There is no single number which answers that question. To answer it, one needs to present the functional relationship across the entire life spans of both dogs and humans, just like in the dog age chart.
References
1 Wang T. et al. (2020) "Quantitative Translation of Dog-to-Human Aging by Conserved Remodeling of the DNA Methylome", Cell Systems, DOI: 10.1016/j.cels.2020.06.006
How to Calculate Dog Years to Human Years
Since the 1950s, the popular calculation of how old a dog was in human years has been that one dog year is the equivalent of seven human years. Even though this formula has been around for a surprisingly long time, the reality is not so cut-and-dried. That doesnt stop people from defaulting to this traditional calculation. You cant really kill the seven-year rule, says Kelly M. Cassidy, a curator of the Charles R. Connor Museum at Washington State University, who compiles studies about longevity in dogs.
One explanation for how this formula got started is that the 7:1 ratio seems to have been based on the statistic that people lived to about 70, and dogs to about 10.
My guess is it was a marketing ploy, says William Fortney, a veterinarian at Kansas State University. He tells the Wall Street Journal that it was a way to educate the public on how fast a dog ages compared to a human, predominantly from a health standpoint. It was a way to encourage owners to bring in their pets at least once a year.
How toCalculate Dog Years to Human Years?
As a general guideline, though, the American Veterinary Medical Association breaks it down like this:
- 15 human years equals the first year of a medium-sized dogs life.
- Year two for a dog equals about nine years for a human.
- And after that, each human year would be approximately five years for a dog.
How Do Researchers Come Up With Those Numbers?
There are many several factors to consider, so its not possible to pin it down precisely, but the AVMA says: Cats and small dogs are generally considered senior at seven years old, but we all know theyve got plenty of life left in them at that age. Larger-breed dogs tend to have shorter lifespans compared to smaller breeds and are often considered senior when they are 5 to 6 years of age. The senior classification is based on the fact that pets age faster than people, and veterinarians start seeing more age-related problems in these pets. Contrary to popular belief, dogs do not age at a rate of 7 human years for each year in dog years.
An example would be the Great Dane. The average life expectancy, according to the Great Dane Club of America, is about 710 years. Therefore, a 4-year-old Great Dane would already be 35 in human years. Again, keep in mind that these are rough estimates.
The National Center for Health Statistics doesnt keep records for dogs. Instead, there are three main sources for data on their longevity: pet-insurance companies, breed-club surveys, and veterinary hospitals.
Why DoSmaller Dogs Live Longer than Larger Dogs?
This phenomenon has baffled scientists for years, and research has yet to explain the relationship between body mass and a dogs lifespan.
Generally speaking, large mammals, like elephants and whales, tend to live longer than small ones, like mice. So why do small dogs have a longer average life span than large breeds?
Large dogs age at an accelerated pace, and their lives seem to unwind in fast motion, according to researcher Cornelia Kraus, an evolutionary biologist at the University of Gttingen in Germany, speaking to Inside Science. Scientists concluded that every 4.4 pounds of body mass reduced a dogs life expectancy by about a month. The reason why is still unknown, though Kraus puts forward several possibilities, including that larger dogs may succumb to age-related illnesses sooner and that the accelerated growth of large dogs may lead to a higher likelihood of abnormal cell growth and death from cancer. Scientists plan future studies to better explain the link between growth and mortality.
Canine gerontology is a burgeoning field of science, as dog lovers are looking to not only extend the time they have with their pets, but to improve the quality of that time. The Dog Aging Project is studying the aging process in dogs, using geroscience research to delay aging and promote healthy longevity.
Whether measured in human years or dog years, as our dogs mature and age there is beauty and charm at every step along the way. With their gray muzzles and wise expressions, senior dogs are especially lovable and poignant.
2019 Epigenetic Clock Study
A2019 studyby researchers at the University of California San Diego put forth a new method for calculating dog age, based on changes made to human and dog DNA over time. In both species, methyl groups are added to DNA molecules throughout aging, altering DNA activity without altering the DNA itself. As a result, DNA methylation has been used by scientists to study aging in humans through an epigenetic clock.
The research team performed targeted DNA sequencing in 104 Labrador Retrievers spanning a 16 year age range, in an attempt to compare dogs epigenetic clocks to those of humans. The results allowed them to derive a formula for adjusting dogs ages to human years, by multiplying the natural logarithm of the dogs age by 16 and adding 31 (human_age = 16ln(dog_age) + 31).Thisnatural logarithm calculatorcan help.
As the study included just a single breed, your own dogs human age based on this formula may not quite match up. Its known that different breeds age differently, so the UCSD formula may lack enough variables for conclusive results. Regardless, the new science-backed formula put forth is certainly more useful to those looking to calculate dogs human age than the long-debunked multiply by 7 myth.
Did You Know?
Evidently, people have been comparing human-to-dog years for centuries.
In 1268, the artisans creating the Cosmati Pavement in Westminster Abbey inscribed into the floor a prediction for Judgement Day: If the reader wisely considers all that is laid down, he will find here the end of the primum mobile; a hedge lives for three years, add dogs and horses and men, stags and ravens, eagles, enormous whales, the world: each one following triples the years of the one before.
By this math, a dog lives to nine, a man to 80. If these statistics were accurate, between 1268 and the mid-20th century, dogs had a year trimmed off their lifespan, and we lost almost a decade. Luckily for both species, our lifespans have gone in the other direction.
If you are the proud owner of a senior dog, celebrate the love they give you with senior dog toys, hip & joint treats, and comfy orthopedic dog beds to make their golden years the best ever.
