Dog Age Calculator
Dog age calculator — enter your dog’s age and size to convert dog years to human years using the updated formula from the American Kennel Club (AKC). The old “multiply by 7” rule is inaccurate — modern veterinary science shows that dogs age faster in their first two years and that larger breeds age significantly faster than smaller ones. A 5-year-old Great Dane is roughly 49 in human years, while a 5-year-old Chihuahua is only about 36.
Dog Years to Human Years Chart (by Size)
This chart uses the size-adjusted formula recommended by the American Veterinary Medical Association (AVMA). During the first year, all puppies age at the same rate regardless of size. After year 2, breed size becomes the dominant factor.
| Dog Years | Small Breed | Medium Breed | Large Breed |
|---|---|---|---|
| 1 | 15 | 15 | 15 |
| 2 | 24 | 24 | 24 |
| 3 | 28 | 29 | 31 |
| 4 | 32 | 34 | 38 |
| 5 | 36 | 39 | 45 |
| 6 | 40 | 44 | 52 |
| 7 | 44 | 49 | 59 |
| 8 | 48 | 54 | 66 |
| 9 | 52 | 59 | 73 |
| 10 | 56 | 64 | 80 |
| 15 | 76 | 84 | 115 |
| 20 | 96 | 104 | 150 |
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Frequently Asked Questions
No, the old “multiply by 7” rule is outdated and inaccurate. Modern veterinary science shows that dogs age differently than that simple formula suggests. The AKC formula (which accounts for size) is much more accurate, as small dogs tend to live longer than large dogs.
A 10-year-old dog’s human age depends on size: Small dogs are about 56 human years old, medium dogs about 64 years, and large dogs about 80 years old. This reflects how larger dogs age faster than smaller breeds.
Larger dogs age faster due to their faster metabolic rates and higher oxygen consumption. This is why a 10-year-old Great Dane is older in human years than a 10-year-old Chihuahua. Size affects longevity across most animal species.
This calculator uses the updated AKC (American Kennel Club) formula: Year 1 = 15 human years, Year 2 = +9 human years (total 24), and each subsequent year adds 4 years for small dogs, 5 for medium, or 7 for large dogs.
Small dogs weigh less than 20 lbs (examples: Chihuahua, Pomeranian), medium dogs weigh 20-50 lbs (Beagle, Cocker Spaniel), and large dogs weigh over 50 lbs (Lab, German Shepherd, Great Dane). Check your dog’s current weight at the vet to be sure.