How Old Am I in Dog Years? — Human to Dog Years Calculator
Enter your age to see what you'd be as a small, medium, or large dog. Because larger dogs age faster, you'd be a “younger dog” as a small breed.
FUN TOOLHow the Reverse Conversion Works
We reverse the DNA methylation formula and size adjustments used in our dog age calculator:
- The math inverts human age = 16 × ln(dog age) + 31
- Small dogs age slower, so more human years = fewer dog years
- Large dogs age faster, so more human years = more dog years
Example: a 30-year-old human would be ~3.5 dog years as a small breed, ~2.5 as a medium breed, and ~2 as a large breed.
Your Age in Dog Years (By Size)
Quick reference chart for common ages:
| Human Age | Small Dog Age | Medium Dog Age | Large Dog Age |
|---|---|---|---|
| 10 | 0.4 | 0.3 | 0.3 |
| 15 | 0.7 | 0.5 | 0.4 |
| 20 | 1.2 | 0.8 | 0.6 |
| 25 | 1.8 | 1.2 | 0.9 |
| 30 | 2.5 | 1.7 | 1.3 |
| 35 | 3.3 | 2.2 | 1.7 |
| 40 | 4.1 | 2.8 | 2.1 |
| 45 | 5.0 | 3.4 | 2.5 |
| 50 | 5.9 | 4.1 | 3.0 |
| 55 | 6.9 | 4.8 | 3.5 |
| 60 | 7.9 | 5.5 | 4.0 |
| 65 | 9.0 | 6.3 | 4.6 |
| 70 | 10.1 | 7.1 | 5.2 |
| 75 | 11.2 | 7.9 | 5.8 |
| 80 | 12.4 | 8.7 | 6.4 |
Fun Dog Age Facts
If you're 21
You'd be about 1.5 years old as a medium dog — barely an adult!
At 50
You'd be 3 years old as a large dog — still in your prime.
At 75
You'd be about 10 as a small dog — just entering senior years.
The oldest human (122)
Would be about 19 as a small dog.
Share Your Dog Age
Tell your friends: “I'm [age] in human years, which is [X] in small dog years, [Y] in medium dog years, and [Z] in large dog years!”
Frequently Asked Questions
Why would I be different ages for different dog sizes?
Large dogs age faster than small dogs. A 7-year-old Great Dane is geriatric, while a 7-year-old Chihuahua is middle-aged. So your human age translates to more dog years for larger breeds.
Is this calculator accurate?
It's based on the same scientific formula used for the dog age calculator (DNA methylation formula with size adjustments), reversed. All dog age conversions are approximations.
What if I want to know my age in cat years?
Cats age differently than dogs. Check our Cat Age Calculator and work backwards from the chart.