How old is my dog in human years?
A dog's first year equals about 15 human years and its second about 9 more (24 in all). After that each year adds about 4 to 7 human years depending on size: a 10-year-old small dog is about 56 in human years, a large dog about 66 and a giant breed about 79. The old “multiply by 7” rule is a myth.
Enter your pet's age and tap Calculate.
Dog age to human years chart
Human-equivalent age by your dog's age and adult size. Between birthdays the calculator above interpolates; past 16 it adds the last yearly step.
| Dog's age | Small up to 9 kg (20 lb) | Medium 10–22 kg (21–50 lb) | Large 23–40 kg (51–90 lb) | Giant over 40 kg (90 lb) |
|---|---|---|---|---|
| 1 year | 15 | 15 | 15 | 12 |
| 2 years | 24 | 24 | 24 | 22 |
| 3 years | 28 | 28 | 28 | 31 |
| 4 years | 32 | 32 | 32 | 38 |
| 5 years | 36 | 36 | 36 | 45 |
| 6 years | 40 | 42 | 45 | 49 |
| 7 years | 44 | 47 | 50 | 56 |
| 8 years | 48 | 51 | 55 | 64 |
| 9 years | 52 | 56 | 61 | 71 |
| 10 years | 56 | 60 | 66 | 79 |
| 11 years | 60 | 65 | 72 | 86 |
| 12 years | 64 | 69 | 77 | 93 |
| 13 years | 68 | 74 | 82 | 100 |
| 14 years | 72 | 78 | 88 | 107 |
| 15 years | 76 | 83 | 93 | 114 |
| 16 years | 80 | 87 | 99 | 121 |
Sizes by adult weight. Content updated 13 October 2026.
Frequently asked questions
Is one dog year equal to seven human years?
No. The “multiply by 7” rule is a myth. Dogs grow up much faster than people in their first two years (a 1-year-old dog is roughly a 15-year-old person) and then age more slowly, and large dogs age faster than small ones. A size-based chart like the one on this page is a better estimate.
How old is a 1-year-old dog in human years?
About 15 human years for small, medium and large dogs, and about 12 for giant breeds. By the second birthday a dog is about 24 in human years (22 for giant breeds).
Why do big dogs age faster than small dogs?
Large and giant breeds have shorter average lifespans, so from about age 5 each year counts for more human years. At 10, a small dog is about 56 in human years, a medium dog about 60, a large dog about 66 and a giant dog about 79.
Which size is my dog?
Use your dog's adult weight: small up to 9 kg (20 lb), medium 10 to 22 kg (21 to 50 lb), large 23 to 40 kg (51 to 90 lb), giant over 40 kg (90 lb). For a puppy, use the weight it is expected to reach as an adult.
How accurate is a dog age calculator?
It is an estimate. The chart is the size-based table widely used by vets, and the American Veterinary Medical Association gives the same rule of thumb: about 15 human years for the first year, about 9 for the second, then about 4 to 5 a year. Breed, genetics and health change how fast an individual dog ages; your vet can tell you more.