How do you convert dog years to human years? Use the AVMA/AKC size model for dogs: a 1-year-old dog is about 15 in human years, a 2-year-old is about 24, and after that a dog adds about 4 to 7 human years per year, depending on its size. This guide is the dog years to human years converter in words: the full conversion table, the model behind it, worked examples, and the common mistakes. Every figure is an estimate, not an exact conversion. The dog age calculator does the same conversion for your dog's exact age and size.
The short version is: do not multiply by seven. A 5-year-old dog is about 39 in human years, not 35, and a 10-year-old dog is about 64, not 70. Use the table below to convert any age from 1 to 15, or the dog age calculator for the exact figure. The how old is my dog in human years guide gives the same model with worked examples.
Dog years to human years converter table
The table below converts dog years to human years for ages 1 to 15, using the AVMA/AKC size model. Find your dog's age in the left column, then read across.
| Dog age | Toy | Small | Medium | Large | Giant |
|---|---|---|---|---|---|
| 1 year | 15 | 15 | 15 | 15 | 15 |
| 2 years | 24 | 24 | 24 | 24 | 24 |
| 3 years | 28 | 28 | 29 | 30 | 31 |
| 5 years | 36 | 36 | 39 | 42 | 45 |
| 7 years | 44 | 44 | 49 | 54 | 59 |
| 10 years | 56 | 56 | 64 | 72 | 80 |
| 12 years | 64 | 64 | 74 | 84 | 94 |
| 15 years | 76 | 76 | 89 | 102 | 115 |
Read the table from top to bottom and the pattern is clear: a dog ages fast in its first two years — 15 human years in the first year, and 24 by the end of the second — and then slows down, but a large dog slows down less than a small one. At age 5, a toy dog is about 36 in human years and a giant dog is about 45; at age 10, the gap is 56 against 80.
How the conversion works
The model most veterinarians use is the AVMA/AKC size model: the first year of a dog’s life equals about 15 human years, the second year brings the total to about 24 human years, and after that you add about 4 human years per dog year for a toy or small dog, about 5 for a medium dog, about 6 for a large dog, and about 7 for a giant dog. The formula for a dog aged two years or more is therefore: human years is approximately 24 plus the dog’s age minus 2, multiplied by the rate for its size.
A second way to estimate a dog’s human age comes from a 2020 epigenetic study by Wang and colleagues at the University of California, San Diego, published in Cell Systems: human age equals 16 times the natural logarithm of the dog’s age, plus 31. For a 5-year-old dog that gives about 57 human years, and for a 10-year-old about 68. The two models agree best in middle age and differ most in very young and very old dogs. The how to calculate dog age guide gives the step-by-step method.
Worked examples
A 1-year-old dog of any size is about 15 in human years. A 2-year-old dog of any size is about 24. A 5-year-old toy dog is 24 plus 3 times 4, which is 36; a 5-year-old medium dog is 24 plus 3 times 5, which is 39; and a 5-year-old giant dog is 24 plus 3 times 7, which is 45. A 10-year-old toy dog is 24 plus 8 times 4, which is 56; a 10-year-old medium dog is 24 plus 8 times 5, which is 64; and a 10-year-old giant dog is 24 plus 8 times 7, which is 80.
To convert your own dog's age, find its age in the table above, or use the dog age calculator. If your dog is between two ages in the table, take the nearer one — the models are estimates, and a year either way does not change the stage of life. The dog age chart by breed guide gives the figures breed by breed, and the dog age chart by size guide gives them by size.
What the converted age means
A dog that is a puppy or kitten needs puppy or kitten food, fed little and often, and gentle exercise while its joints are still developing. An adult dog needs measured food and daily exercise, and a vet check once a year. A senior dog needs twice-yearly vet checks, a diet review, and exercise that stays regular but gentler. The converted age is a guide to the stage, not a prescription — and a dog's weight, health, and activity matter as much as its age.
Once a dog passes its senior boundary — about 10 years for a toy or small dog, 8 to 10 for a medium dog, 7 to 8 for a large dog, and 6 to 7 for a giant dog — expect gradual change rather than a sudden switch: sleep increases, play sessions get shorter, and the dog may become more set in its routines. The senior dog diet guide covers feeding in the senior years, and the when is a dog considered a senior guide gives the thresholds by size.
Common mistakes
The most common mistake is the 'multiply by seven' rule: multiplying by seven gives 35 human years for a 5-year-old dog, against about 39 on the size model — and it is wrong in the other direction for puppies and kittens, where a 1-year-old dog is already about 15 in human years, not 7. The second mistake is using the dog model for a cat, or the cat rule for a dog: dogs and cats age differently, and the models are not interchangeable.
The third mistake is taking the number too literally: the models give an estimate of the stage of life, not an exact conversion, and two dogs of the same age can be in very different shape. The fourth is forgetting size for dogs: a large dog ages faster than a small one, so a 10-year-old Great Dane is much older in human years than a 10-year-old Chihuahua. The dog lifespan calculator puts age in the context of lifespan.
For related reading, see the dog age calculator, the dog age calculator guide, the how old is my dog in human years guide, the how to calculate dog age guide, the dog age chart by size guide, the dog lifespan estimator.
Frequently asked questions
How do I convert dog years to human years?
Use the AVMA/AKC size model for dogs: a 1-year-old dog is about 15 in human years, a 2-year-old is about 24, and after that a dog adds about 4 to 7 human years per year, depending on its size. Find your dog's age in the table above, or use the dog age calculator for the exact figure.
How old is a 5-year-old dog in human years?
A 5-year-old toy or small dog is about 36, a medium dog about 39, a large dog about 42, and a giant dog about 45.
How old is a 10-year-old dog in human years?
A 10-year-old toy or small dog is about 56 in human years, a medium dog about 64, a large dog about 72, and a giant dog about 80.
Is the 'multiply by 7' rule right?
No. Multiplying by seven gives 35 human years for a 5-year-old dog, against about 39 on the size model — and it is wrong in the other direction for puppies and kittens, where a 1-year-old dog is already about 15 in human years, not 7.
When is a dog considered a senior?
A dog is usually considered a senior from about 10 years for a toy or small dog, 8 to 10 for a medium dog, 7 to 8 for a large dog, and 6 to 7 for a giant dog. Those are rough guides, and your vet may move the boundary earlier or later depending on your individual dog's health.
How long do dogs live?
Typical lifespans by size are about 12 to 16 years for toy breeds, 12 to 15 for small breeds, 10 to 14 for medium breeds, 10 to 12 for large breeds, and 7 to 10 for giant breeds. Those are ranges, not promises.
Results on this page are estimates for general information only and are not veterinary advice. If your pet is ill, underweight, overweight, pregnant, or has a health condition, consult your veterinarian before changing diet or care.