Dog age calculator: your dog's age in human years
Updated By PetymFacts checked against official sources on
Quick answer
By the 2020 DNA-methylation formula of Wang et al., a 1-year-old dog is about 31 in human years, a 4-year-old about 53 and a 10-year-old about 68. Enter your dog's age and size to see its number, Merck's simpler rule beside it, and the life stage AAHA recommends vets use. The old "multiply by 7" rule is a myth, the American Veterinary Medical Association says.
How old is your dog in human years?
Enter the age in years and months, and the size your dog is or will be when grown.
Dog age calculator
Your dog's age in human years, from the 2020 DNA study and Merck's rule of thumb, with the life stage.
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Your dog
Enter an age to see your dog's number and life stage.
Is one dog year really seven human years?
"Contrary to popular belief, dogs do not age at a rate of 7 human years per dog year," says the American Veterinary Medical Association. UC Davis's veterinary school says the rule probably comes from average lifespans of about 10 years for dogs and 70 for people, and that dogs age much faster than people in their first years.
How does the calculator work it out?
The calculator uses the formula from a 2020 study in Cell Systems by Wang and colleagues at UC San Diego, who compared age-related changes in the DNA of about 100 dogs, almost all Labrador retrievers aged up to 16, with the same changes in people: human age = 16 × ln(dog age) + 31, where ln is the natural logarithm. The study found a dog's first years count for much more than its later ones.
It gives a number only from 1 to 16 years, the ages the study covered. Below about 7.5 weeks the formula even turns negative, and the study had no dogs between about 7 months and a year, so for puppies the calculator shows the life stage instead. Merck's Veterinary Manual uses a simpler rule, about 10 to 12 human years for each of a dog's first two years, then about 4 a year, and it gives lower numbers for young dogs, so the calculator shows it beside the formula.
Dog age chart: 1 to 16 years in human years
| Dog's age | Wang 2020 formula | Merck's rule of thumb |
|---|---|---|
| 1 year | 31 | 10 to 12 |
| 2 years | 42 | 20 to 24 |
| 3 years | 49 | 24 to 28 |
| 4 years | 53 | 28 to 32 |
| 5 years | 57 | 32 to 36 |
| 6 years | 60 | 36 to 40 |
| 7 years | 62 | 40 to 44 |
| 8 years | 64 | 44 to 48 |
| 9 years | 66 | 48 to 52 |
| 10 years | 68 | 52 to 56 |
| 11 years | 69 | 56 to 60 |
| 12 years | 71 | 60 to 64 |
| 13 years | 72 | 64 to 68 |
| 14 years | 73 | 68 to 72 |
| 15 years | 74 | 72 to 76 |
| 16 years | 75 | 76 to 80 |
When is a dog a senior?
It depends on size: bigger dogs usually have shorter lives and become seniors earlier. In a 2022 study of 93 breeds, median lifespans ran from 6.3 years for the Great Dane to 14.6 for the Toy Poodle. The American Veterinary Medical Association counts dogs as seniors at these ages, from American Kennel Club data:
- Small or toy (under about 9 kg): from 8 to 11 years
- Medium (about 9 to 23 kg): from 8 to 10 years
- Large (about 23 to 41 kg): from 8 to 9 years
- Giant (over about 41 kg): from 6 to 7 years
Merck's Veterinary Manual counts dogs over 7 to 8 years as seniors and suggests vet visits twice a year or more from then on. AAHA, the American Animal Hospital Association, defines a senior by the last quarter of the dog's expected lifespan rather than by a fixed age.
Does it work for Indian dogs?
No Indian study we could find gives age-conversion figures for Indian breeds or indie dogs, so the calculator applies the same published methods to every dog.
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Questions owners ask
How old is my dog in human years?
- By the 2020 formula of Wang et al., a 2-year-old dog is about 42 in human years, a 7-year-old about 62 and a 12-year-old about 71. Merck's simpler rule gives lower numbers for young dogs, 20 to 24 at age 2, so treat any single number as approximate.
Is one dog year really seven human years?
- No. The American Veterinary Medical Association says dogs do not age at 7 human years per dog year; they age fastest in their first years and more slowly after.
Does the calculator work for indie dogs and small breeds?
- It works the same way for every dog, but the formula was built almost entirely on Labrador retrievers, and bigger dogs usually have shorter lives. No Indian study we could find gives age-conversion figures for indie dogs.
Why does the calculator give no human age for a puppy?
- Worked out from the formula, the number turns negative below about 7.5 weeks, and the study had no dogs between about 7 months and a year. For a puppy the calculator shows its life stage instead, and Merck's rough 10 to 15 human years for 6 to 12 months.
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Sources
Each source was opened and read on the date shown. How Petym checks its sources
- AVMA: Caring for senior cats and dogs (read in the web-archive copy of 4 Oct 2026) (opens in a new tab)
- AAHA (JAAHA): 2019 AAHA Canine Life Stage Guidelines (opens in a new tab)
- UC Davis School of Veterinary Medicine: Calculating your dog's age (read in the web-archive copy of 28 Sep 2026) (opens in a new tab)
- Merck Veterinary Manual: Description of dogs (opens in a new tab)
- Merck Veterinary Manual: Table: dog years versus human years (opens in a new tab)
- Merck Veterinary Manual: Routine health care of dogs (opens in a new tab)
Show all 12 sourcesShow fewer
- University of California (UC San Diego): How dogs actually age (2020) (opens in a new tab)
- Cell Systems (2020), UC San Diego: Quantitative translation of dog-to-human aging by conserved remodeling of the DNA methylome (Wang et al.) (opens in a new tab)
- PNAS (2022): DNA methylation clocks for dogs and humans (Horvath et al.) (opens in a new tab)
- Nucleic Acids Research (2025): Dog10K: an integrated database summarizing canine multi-omics (opens in a new tab)
- Frontiers in Veterinary Science (2021), University of Nottingham: How old is my dog? Rational age groupings in pet dogs (opens in a new tab)
- Journal of Veterinary Science (2025), Seoul National University: Diverse breeds, diverse lifespans: understanding longevity in domestic dogs (opens in a new tab)