Dog age calculator
Data reviewed August 1, 2026
Quick answer
Result
~53 human years
Life stage: adult. Typical lifespan for a medium dog is 12 to 15 years.
Formula: 16 × ln(age) + 31, from Wang et al., Cell Systems 2020.
Why the 7-year rule fails
Dogs reach adolescence in under a year and full maturity by two, so early dog years "count" far more than later ones. The UCSD team matched epigenetic clocks (DNA methylation patterns) between 104 Labrador Retrievers and human reference data, producing the logarithmic curve this calculator uses. Size matters at the end of life: small breeds commonly live 14 to 17 years while giant breeds average 8 to 10, so we show a size-adjusted life-stage readout alongside the formula.
Frequently asked questions
How do I convert dog years to human years?
Use the research formula: human age = 16 × ln(dog's age in years) + 31, for dogs at least 1 year old. A 2-year-old dog is about 42 human years; an 8-year-old is about 64.
Is one dog year really 7 human years?
No. The 7:1 ratio is a marketing-era myth. Epigenetic research shows dogs age extremely fast in their first two years and much more slowly after, following a logarithmic curve.
Do small dogs age slower than big dogs?
They live longer. Small breeds commonly reach 14 to 17 years while giant breeds average 8 to 10. The methylation formula was calibrated on Labrador Retrievers, so treat it as an approximation and adjust life-stage expectations by size.
Sources
We only publish numbers we can attribute. How we build estimates: methodology.