🐕 Dog Age Calculator (Dog Years to Human Years)
Enter your dog's age to see it in human years — with the modern epigenetic-clock estimate and the traditional size-based one side by side.
Epigenetic estimate
53 human years
2020 DNA-methylation study (16 × ln(age) + 31)
Traditional (size-based)
34 human years
15 first year, +9 second, then by size
The old "multiply by 7" rule is a myth — dogs mature fast early then slow down. The epigenetic formula (from a 2020 study comparing dog and human DNA methylation) captures that curve. The traditional estimate uses the AVMA figures (15 the first year, +9 the second); the per-size increments after that are a common convention reflecting that larger breeds age faster, not an official standard. Both are population estimates. 🔒 In your browser.
How the dog age calculator (dog years to human years) works
Dogs don't age at a steady 7-to-1 ratio: they mature very quickly in the first two years, then slow down. The tool shows two estimates. The epigenetic formula from a 2020 study — human age = 16 × ln(dog age) + 31 — was derived by comparing DNA methylation ("molecular ageing") in dogs and humans. The traditional estimate counts the first year as about 15 human years, the second as about 9 more (≈ 24), then adds a per-year amount that grows with the dog's size, since larger breeds age faster.
Both are population-level estimates, not a clinical measurement of your individual dog. The epigenetic study was based on Labradors; the size-based per-year increments after age two are a common convention rather than an official standard. Bigger dogs generally have shorter lifespans, which is why they "age" faster in the size-based view.
Frequently asked questions
How do I calculate my dog's age in human years?
Not by multiplying by 7 — that's a myth. A better estimate is the epigenetic formula: human age = 16 × ln(dog age in years) + 31. So a 4-year-old dog is about 16 × ln(4) + 31 ≈ 53 human years. The tool also shows a traditional size-based estimate.
Is the "multiply by 7" rule accurate?
No. Dogs mature much faster than humans early on — a 1-year-old dog is roughly a 15-year-old human, not 7 — then age more slowly. The 7× rule badly misjudges both ends. Use the epigenetic or size-based methods instead.
Why do large dogs age faster than small dogs?
Larger breeds have shorter lifespans and reach "old age" sooner, so each calendar year counts for more human-equivalent years. That's why the traditional estimate adds more per year for big and giant breeds than for small ones.
What is the epigenetic dog age formula?
From a 2020 study (Wang et al.), human age = 16 × ln(dog age) + 31, based on how chemical marks (methylation) accumulate on DNA in both species. It captures the fast-then-slow ageing curve better than a fixed ratio.
How old is a 10-year-old dog in human years?
By the epigenetic formula, about 16 × ln(10) + 31 ≈ 68 human years. The size-based estimate varies: a small dog might be ~56 and a giant breed considerably older. Enter your dog's size for that view.