Puppy Weight
Calculator
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Pets
Dog Age Calculator
Convert your dog’s age to human years using the size-adjusted vet chart — not the old 7-year myth.
Human age
—
In human years.
| Life stage | — |
|---|---|
| Ageing rate now | — |
| Another method | — |
| Dog’s age | — |
Show our math
Enter your figures above to see the step-by-step working.
A friendly estimate — ask your vetEverything computed client-side — nothing leaves this page
How the Dog Age Calculator Works
The old “one dog year equals seven human years” rule is a myth. Dogs mature fast early on, then age more slowly — and larger breeds age quicker than small ones. This calculator uses the veterinary chart most vets follow: the first year counts as about 15 human years, the second adds 9 (reaching 24), and every year after that adds 4 to 7 depending on your dog’s size.
For comparison it also shows the 2019 epigenetic estimate — a formula from DNA-methylation research, human age = 16 × ln(dog age) + 31 — which lines up closely for adult dogs. Either way, a “senior” dog is younger in calendar years than most people assume, especially for giant breeds.
human age = 15 (year 1) + 9 (year 2) + (age − 2) × size rate
Note: a friendly estimate based on common averages. Breeds vary widely — your veterinarian knows your pet best.
Frequently Asked Questions
How old is my dog in human years?
Not simply seven times its age. The first year is about 15 human years, the second brings it to 24, and each further year adds 4–7 depending on size. Enter your dog’s age and size for the estimate.
Why do big dogs age faster?
Larger breeds have shorter lifespans and reach old age sooner, so each later year counts for more human years — about +6 to +7 for large and giant breeds versus +4 for small ones.
Is the 7-year rule accurate?
No. It over-simplifies. Dogs age rapidly in their first two years then more gradually, and size matters, which is why this calculator uses the size-adjusted veterinary chart.
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