4 dog years to human years by size
| Dog size | Human age | Life stage |
|---|---|---|
| Small (20 lb or less) | 32 | mature adult |
| Medium (21 to 50 lb) | 32 | mature adult |
| Large (51 to 100 lb) | 32 | mature adult |
| Giant (over 100 lb) | 38 | mature adult |
The old "multiply by seven" rule would say 28. The DNA-based formula from UC San Diego (16 × ln(4) + 31) gives 53. That formula was built on Labradors, so it fits medium and large dogs best.
What 4 looks like for a dog
Four is solidly adult. Keep an eye on weight. Middle-age spread starts here, and over half of US dogs are overweight.
Frequently asked questions
How old is a 4 year old dog in human years?
Between 32 and 38 human years. Small dogs (under 20 lb) are about 32, medium dogs 32, large dogs 32 and giant breeds 38.
Is a 4 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 not yet.