Fitness age in dog years
Your watch says your fitness age is 42. What is that in dog years? Research has a better answer than dividing by 7.
Your details
Your fitness age of 42 in dog years
2.0 dog years
8 years younger than your real age
- Your real age, in dog years3.3
- Old rule (divide by 7)6.0
- Formulahuman age = 16 ln(dog age) + 31 (Wang 2020)
The 2020 Labrador study found dogs age fast early and slow down later, so the old rule of 7 is way off. Fitness age comes from your watch or a fitness test, and moving more is the quickest way to make it younger.
The working
Age 50, fitness age 42
The 2020 formula says human age = 16 ln(dog age) + 31, so dog age = e^((human age - 31) / 16). A fitness age of 42 is e^(11/16) = 2.0 dog years; your real age of 50 is 3.3. The old rule of 7 would say 6.0.
Dog to human
From the formula
| Dog age | Human age |
|---|---|
| 1 | 31 |
| 2 | 42 |
| 4 | 53 |
| 8 | 64 |
| 12 | 71 |
Fitness age
What it means
Fitness age compares your estimated fitness (VO2 max) with the average for each age. Watches and fitness tests estimate it. Being more active is the quickest way to lower it.
Read with care
What this cannot tell you
- Measure fitnessUse a watch, a test or a fitness professional.
- Work for every dogThe formula came from Labradors; small breeds age differently.
- Tell you your real ageYou probably know that one.
Questions
Common questions
Is one dog year 7 human years?
No. Dogs age very fast in their first two years and then slow down, so a 1 year old dog is more like a 31 year old human.
Where does the formula come from?
A 2020 study in Cell Systems compared DNA changes with age in 104 Labradors and in humans.
What is a fitness age?
Your age compared with others who share your fitness level, usually from VO2 max.
How can I lower my fitness age?
Regular moderate and vigorous activity raises VO2 max; even a few months helps.
Sources
- Wang T et al. Quantitative translation of dog-to-human aging. Cell Systems 2020 (human age = 16 ln(dog age) + 31)
- UK Chief Medical Officers' physical activity guidelines (2019)
- Herrmann SD et al. 2024 Adult Compendium of Physical Activities. J Sport Health Sci 2024;13:6-12 (codes noted beside each value; two walking and running values are from the 2011 Compendium)
Last checked 21 October 2026. Spotted something wrong? Tell us and we will fix it.
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