6 dog years to human years by size
| Dog size | Human age | Life stage |
|---|---|---|
| Small (20 lb or less) | 40 | mature adult |
| Medium (21 to 50 lb) | 42 | mature adult |
| Large (51 to 100 lb) | 45 | mature adult |
| Giant (over 100 lb) | 49 | senior |
The old "multiply by seven" rule would say 42. The DNA-based formula from UC San Diego (16 × ln(6) + 31) gives 60. That formula was built on Labradors, so it fits medium and large dogs best.
What 6 looks like for a dog
At six, giant breeds like Great Danes are already seniors. Small dogs are only around 40 in human terms.
Frequently asked questions
How old is a 6 year old dog in human years?
Between 40 and 49 human years. Small dogs (under 20 lb) are about 40, medium dogs 42, large dogs 45 and giant breeds 49.
Is a 6 year old dog a senior?
For a small dog, no (mature adult). For a large dog it is not yet, and for a giant breed it is yes.