How old is my dog in human years?
Convert dog years to human years with the American Kennel Club's chart, which depends on your dog's adult size. The calculator also shows the newer DNA-clock estimate and your dog's life stage.
Dog years to human years chart
The American Kennel Club's chart, in human years, by your dog's adult weight. The last column is the DNA-clock formula from UC San Diego's study of Labrador retrievers, rounded to whole years.
| Dog's age | Small 20 lb or less | Medium 21–50 lb | Large 51–100 lb | Giant over 100 lb | DNA clock Labradors |
|---|---|---|---|---|---|
| 1 year | 15 | 15 | 15 | 12 | 31 |
| 2 years | 24 | 24 | 24 | 22 | 42 |
| 3 years | 28 | 28 | 28 | 31 | 49 |
| 4 years | 32 | 32 | 32 | 38 | 53 |
| 5 years | 36 | 36 | 36 | 45 | 57 |
| 6 years | 40 | 42 | 45 | 49 | 60 |
| 7 years | 44 | 47 | 50 | 56 | 62 |
| 8 years | 48 | 51 | 55 | 64 | 64 |
| 9 years | 52 | 56 | 61 | 71 | 66 |
| 10 years | 56 | 60 | 66 | 79 | 68 |
| 11 years | 60 | 65 | 72 | 86 | 69 |
| 12 years | 64 | 69 | 77 | 93 | 71 |
| 13 years | 68 | 74 | 82 | 100 | 72 |
| 14 years | 72 | 78 | 88 | 107 | 73 |
| 15 years | 76 | 83 | 93 | 114 | 74 |
| 16 years | 80 | 87 | 99 | 121 | 75 |
AKC values from its dog-years chart. DNA clock: 16 × ln(age) + 31, from Wang et al., Cell Systems (2020). The AKC weight groups are rounded; for a dog near a boundary, ask your vet which fits.
Why dog years aren't multiples of 7
The old rule says one dog year equals seven human years. The AKC, citing the AVMA, says that isn't how dogs age. Dogs mature fast: on the AKC chart a dog's first year counts as 15 human years (12 for a giant dog) and two years as 24 (22 for a giant dog). After that, each year adds about 4 human years for a small dog, 4 to 6 for a medium one, and up to 7 to 9 for large and giant dogs. So size matters more as dogs get older, which is why the calculator asks for your dog's adult weight.
The DNA-clock formula
In 2020, researchers at UC San Diego compared the chemical tags on DNA, called methylation, in Labrador retrievers and in people. These patterns change with age in both species, so the team could match a dog's age to the human age with similar patterns. The result, published in Cell Systems, is a curve rather than a straight line: human age = 16 × ln(dog age) + 31, where ln is the natural logarithm.
By that formula a 1-year-old dog is similar to a 30-year-old person and a 4-year-old dog to a 52-year-old, and dogs' aging slows after about 7. It gives much older figures for young dogs than the AKC chart does. The researchers note one limit: it comes from a single breed, Labrador retrievers, and some breeds live longer than others. The AKC chart takes your dog's size into account; the formula shows how quickly young dogs mature.
Dog life stages
Vets plan care by life stage rather than by human-age equivalents. The AAHA's 2019 guidelines use five stages:
| Stage | When |
|---|---|
| Puppy | From birth until rapid growth stops, at about 6 to 9 months depending on breed and size |
| Young adult | Until physical and social maturity, which most dogs reach by 3 to 4 years |
| Mature adult | From maturity until the last 25% of the expected lifespan |
| Senior | The last 25% of the expected lifespan |
| End of life | The final stage, depending on the dog's illness |
Source: AAHA 2019 Canine Life Stage Guidelines. The AAHA gives no fixed ages for mature adult and senior, because dogs vary more as they age; the expected lifespan depends mainly on breed.
For a cat, see cat years to human years; both are in the pet age calculator.
Questions owners ask
How old is a 1-year-old dog in human years?
About 15 on the AKC chart for small, medium and large dogs, and 12 for giant dogs. The DNA-clock formula from UC San Diego puts a 1-year-old Labrador closer to 30.
Is one dog year equal to seven human years?
No. The AKC, citing the AVMA, says dogs don't age at 7 human years a year. They age fastest at first: the first two years count as about 24 human years, then each year adds about 4 for a small dog and up to 7 to 9 for large and giant dogs.
How old is a 10-year-old dog in human years?
On the AKC chart: 56 for a small dog, 60 for a medium dog, 66 for a large dog and 79 for a giant dog. The DNA-clock formula gives about 68.
When is a dog a senior?
The AAHA's life stage guidelines count a dog as a senior for the last 25% of its expected lifespan, which depends on breed and size. That is why there is no single senior age for every dog.
Do small dogs age more slowly?
After the first two years, yes: on the AKC chart, a small dog adds about 4 human years a year, while large and giant dogs add more.