How to use it
Enter your dog's age
Type the age in years — decimals like 2.5 are fine.
Pick a size band
Choose small, medium, large or giant based on adult body weight.
Compare both results
Read the DNA-based estimate and the size-adjusted vet table value side by side.
About the dog age calculator
The old "multiply by 7" rule is a rough myth. This calculator uses the formula from the UC San Diego 2020 DNA-methylation study, which compared epigenetic aging clocks in dogs and humans and found the relationship human years = 16 × ln(dog years) + 31 for dogs one year and older (younger puppies are estimated at roughly 15 human years per dog year). Because breeds age at different speeds, it also shows the classic size-adjusted veterinary chart, interpolated for the age you enter.
| Dog years | Small <10 kg | Medium 10–25 kg | Large 25–45 kg | Giant >45 kg |
|---|---|---|---|---|
| 1 | 15 | 15 | 15 | 14 |
| 2 | 24 | 24 | 24 | 22 |
| 3 | 28 | 28 | 28 | 31 |
| 5 | 36 | 36 | 40 | 45 |
| 7 | 44 | 47 | 50 | 56 |
| 10 | 56 | 60 | 66 | 78 |
| 12 | 64 | 69 | 77 | 93 |
| 15 | 76 | 83 | 93 | 115 |
Questions
Isn't one dog year just seven human years?
No — that rule of thumb doesn't match how dogs actually age. Dogs mature very quickly early in life and then slow down: a 2-year-old dog is roughly 24 human years, not 14. The logarithmic DNA-based formula captures this fast-then-slow pattern much better than any straight multiplier.
Why does size matter?
Large and giant breeds age faster and have shorter average lifespans than small breeds. A 10-year-old giant breed is biologically much "older" than a 10-year-old toy breed, which is why the size-adjusted table diverges from about age 3 onward.
Is anything uploaded?
No. The calculation runs entirely in your browser — nothing is sent to a server, and no account is needed.
Is this veterinary advice?
No. Both numbers are population-level estimates for general interest. Individual dogs vary with breed, genetics and health, so always consult a veterinarian for decisions about your dog's care.