Dog Age Calculator: Dog Years to Human Years
Enter your dog’s age and size (or breed) to see how old your dog is in human years – based on the veterinary chart, not the old “multiply by 7” myth.
Don’t know your dog’s age? Upload a photo and our AI estimates it from visible signs like the muzzle, eyes and coat: pet age from photo.
Why “1 dog year = 7 human years” is wrong
Dogs grow up very fast: a one-year-old dog is already an adult, roughly like a 15-year-old human, and a two-year-old dog is about 24. After that, dogs age more slowly – and size matters. Small dogs live longer and age more slowly than large and giant breeds, which is why a 10-year-old Chihuahua is “younger” than a 10-year-old Great Dane.
Dog age chart
Human-year equivalents by dog size (based on the chart used by veterinary organizations such as the AVMA):
| Dog age | Small (≤20 lb) | Medium (21–50 lb) | Large (51–100 lb) | Giant (>100 lb) |
|---|---|---|---|---|
| 1 | 15 | 15 | 15 | 12 |
| 2 | 24 | 24 | 24 | 22 |
| 3 | 28 | 28 | 28 | 31 |
| 4 | 32 | 32 | 32 | 38 |
| 5 | 36 | 36 | 36 | 45 |
| 6 | 40 | 42 | 45 | 49 |
| 7 | 44 | 47 | 50 | 56 |
| 8 | 48 | 51 | 55 | 64 |
| 9 | 52 | 56 | 61 | 71 |
| 10 | 56 | 60 | 66 | 79 |
| 11 | 60 | 65 | 72 | 86 |
| 12 | 64 | 69 | 77 | 93 |
| 13 | 68 | 74 | 82 | 100 |
| 14 | 72 | 78 | 88 | 107 |
| 15 | 76 | 83 | 93 | 114 |
| 16 | 80 | 87 | 99 | 121 |
The new DNA formula (2020 study)
Researchers at the University of California San Diego compared chemical changes in DNA (methylation) in Labrador Retrievers and humans. Their formula is human age = 16 × ln(dog age) + 31. It says a 1-year-old dog is like a 31-year-old human and a 4-year-old dog like a 53-year-old. It was built on one breed, so we show it as a second opinion next to the size-based chart.
Dog life stages
- Puppy: birth to about 6 months – fast growth, baby teeth, lots of sleep.
- Junior / adolescent: 6 months to 2 years – adult size, lots of energy, testing limits.
- Adult: from about 2 years until the mature years.
- Mature and senior: small dogs from about 10–11 years, medium dogs from about 10, large dogs from about 8 and giant breeds from about 7.
Senior dogs benefit from vet checkups every 6 months, joint support and an adjusted diet.
How to tell how old a dog is
- Teeth: puppies get adult teeth by about 6 months; white, clean teeth suggest a young dog, while tartar, wear and missing teeth point to middle or old age.
- Gray hair: a gray muzzle usually starts from about 5–7 years (earlier in some breeds).
- Eyes: a bluish haze (lenticular sclerosis) is common from around 6–7 years.
- Body and energy: muscle loss, stiffness and more sleep are signs of a senior dog.
Our AI pet age estimator checks these signs on a photo, and a vet can narrow it down with a dental exam.
Frequently asked questions
How old is a 5-year-old dog in human years?
About 36 human years for small, medium and large dogs, and about 45 for giant breeds. From year 6 on, larger dogs age noticeably faster.
How long do dogs live?
Most dogs live 10–13 years. Small breeds often reach 14–16, while giant breeds usually live 8–10 years.
What about mixed-breed dogs?
Choose the size that matches your dog’s adult weight.