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Dog Age Calculator
Turn your dog's age into human years two ways: the AVMA rule of thumb vets quote, and the 2020 DNA-methylation formula from a study of Labradors, side by side.
Dog Age Calculator: The AVMA rule, as quoted by the American Kennel Club, counts the first year of a medium-sized dog as about 15 human years, the second as about 9 more, and each year after as about 5. The DNA clock is the formula 16 × ln(dog age) + 31 from Wang and colleagues, published in Cell Systems in 2020 after measuring DNA methylation in 104 Labrador retrievers. Runs 100% locally in your browser with zero server file uploads.
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About 34 in human years
AVMA ruleThe two disagree most in young dogs: the DNA study found that dogs age very fast early on and slowly later. The AVMA rule is for medium-sized dogs; large breeds age faster and small breeds more slowly.
| Dog's age | AVMA rule | DNA clock (2020) |
|---|---|---|
| 1 y | 15 | 31 |
| 2 y | 24 | 42 |
| 3 y | 29 | 49 |
| 4 y | 34 | 53 |
| 5 y | 39 | 57 |
| 6 y | 44 | 60 |
| 7 y | 49 | 62 |
| 8 y | 54 | 64 |
| 9 y | 59 | 66 |
| 10 y | 64 | 68 |
| 12 y | 74 | 71 |
| 14 y | 84 | 73 |
| 16 y | 94 | 75 |
Two ways to count dog years
The rule quoted from the American Veterinary Medical Association is a developmental guide: a medium-sized dog reaches adolescence and adulthood within its first two years, roughly what a person does by their mid-twenties, and ages more slowly after that. The DNA clock published by Wang and colleagues in 2020 compared methylation, chemical marks on DNA that change with age, in Labradors and in people, and fitted a logarithmic curve to the match.
The clock agrees with milestones at both ends: by their figures, a Labrador's average lifespan of about 12 years corresponds to a human life expectancy of about 70. In between, it makes a young dog much older than the rule does: a four-year-old Labrador comes out at about 53.
Size, breed, and life stages
Large and giant breeds live shorter lives than small ones, so after the first years they age faster in human terms. Neither method adjusts for that: the rule assumes a medium-sized dog, and the clock was measured only in Labradors. The AAHA canine life stage guidelines therefore define the senior stage by lifespan rather than age: the last quarter of the life a dog of that size and breed can expect.
For a cat, use the cat age calculator; for a person's exact age in years, months, and days, the age calculator.
How to use it
- Enter your dog's age in years and months.
- Read the age in human years by the AVMA rule and by the DNA clock.
- Compare them in the table for every age from 1 to 16.
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Frequently asked questions
Is one dog year really seven human years?
No. Dogs grow up much faster than people in their first two years and then age more slowly, so a single multiplier is wrong at both ends. By the AVMA rule a one-year-old dog is about 15, not 7.
Why do the two methods give different ages?
They measure different things. The AVMA rule is a rough guide from how dogs develop; the DNA clock compares chemical changes on the DNA of dogs and people. The clock makes young dogs much older and old dogs a little younger than the rule does.
Does size matter?
Yes. Large and giant breeds have shorter lives and age faster after the first couple of years, while small breeds age more slowly. The AVMA rule is for a medium-sized dog, and the DNA clock was measured only in Labradors.
When is a dog a senior?
The AAHA's canine life stage guidelines call a dog a senior in the last quarter of its expected lifespan, which comes earlier in large breeds than in small ones. Ask your vet when your dog's senior check-ups should start.
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