Free Dog Age Calculator
This dog age calculator turns dog years into human years. Enter your dog's age and adult weight; the answer updates as you type.
Or browse the dog age chart by breed. Also see the dog food calculator, or estimate a puppy's adult size with the puppy weight calculator.
Dog age chart: dog years to human years
Use this chart like a dog years calculator when you just need a quick look-up.
| Dog age | Small | Medium | Large | Giant | UCSD formula |
|---|---|---|---|---|---|
| 1 | 15 | 15 | 15 | 12 | 31 |
| 2 | 24 | 24 | 24 | 22 | 42 |
| 3 | 28 | 28 | 28 | 31 | 49 |
| 4 | 32 | 32 | 32 | 38 | 53 |
| 5 | 36 | 36 | 36 | 45 | 57 |
| 6 | 40 | 42 | 45 | 49 | 60 |
| 7 | 44 | 47 | 50 | 56 | 62 |
| 8 | 48 | 51 | 55 | 64 | 64 |
| 9 | 52 | 56 | 61 | 71 | 66 |
| 10 | 56 | 60 | 66 | 79 | 68 |
| 11 | 60 | 65 | 72 | 86 | 69 |
| 12 | 64 | 69 | 77 | 93 | 71 |
| 13 | 68 | 74 | 82 | 100 | 72 |
| 14 | 72 | 78 | 88 | 107 | 73 |
| 15 | 76 | 83 | 93 | 114 | 74 |
How the dog age calculator works
- Size-based chart: a widely published table by size, which matches the AKC guideline for medium dogs. Small to large dogs are about 15 at year one and 24 at year two (giant dogs 12 and 22); after that bigger dogs age faster, so 10 dog years is 56 human years for a small dog but 79 for a giant one.
- UCSD formula: human age = 16 × ln(dog age in years) + 31. It tracks how DNA methylation changes with age and does not depend on size, so it gives the same answer for every breed.
- Life stage: puppy until about 1 year (1.5 for large, 2 for giant breeds); senior over the last quarter of the typical lifespan for the size class.
Sources differ by a few years on every chart, so treat any single number as an estimate. Your vet can tell you what life stage care your dog needs.
Dog age by breed
- Chihuahua
- Yorkshire Terrier
- Pomeranian
- Maltese
- Shih Tzu
- Pug
- Dachshund
- French Bulldog
- Boston Terrier
- Miniature Schnauzer
- Cavalier King Charles Spaniel
- Beagle
- All breeds →
Frequently asked questions
How does the dog age calculator work?
It converts dog years to human years two ways: a size-based chart, because bigger dogs age faster, and the UCSD research formula. Enter age and weight and both answers update instantly.
How old is my dog in human years?
Enter your dog's age and adult weight above to see its age in human years. As a rule of thumb, a 1-year-old dog is about 15, a 2-year-old about 24, and each year after that adds 4 to 7 human years depending on size.
How do you calculate dog years?
The old rule of 7 dog years per human year is too simple. A common chart gives 15 human years for a dog's first year, 9 more for the second, then 4 to 7 per year depending on size. A newer method from University of California San Diego researchers uses the formula human age = 16 × ln(dog age) + 31.
Why do big dogs age faster?
Larger breeds tend to have shorter lifespans, so each calendar year represents more of their life. A Great Dane at 7 is roughly as old as a small dog at 10 or 11.
How old is a 1-year-old dog in human years?
About 15 years on the size-based chart (12 for giant breeds) and about 31 years on the UCSD formula. Both agree that a dog is an adult by its first birthday.
Which method is more accurate?
Neither is exact. The UCSD formula was built from DNA changes in Labrador Retrievers, so it is best for medium and large dogs. The size-based chart is simpler and adjusts for size. We show both so you can compare.