← Back to the Dog & Cat Age Calculator
Work it backwards — enter a human age and see the equivalent age in dog years for each size.
| Dog size | Dog age |
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Dogs age fast in their first two years, then slow down — so the conversion works backwards the same way. Up to 15 human years is the first dog year, and 24 human years is two dog years. After that, each dog year adds about 4 human years for small dogs, 5 for medium, 6 for large and 7 for giant breeds. That is the same size-based method used by veterinary guidance (AKC, based on AVMA), just run in reverse.
For example, 39 human years is about 5 dog years for a medium dog: 2 + (39 − 24) ÷ 5 = 5. The same 39 years is about 5.8 dog years for a small dog and about 4.1 for a giant dog, because larger breeds reach a human age in fewer dog years.
Equivalent dog age for common human ages, by adult size. Figures are estimates.
| Human years | Small | Medium | Large | Giant |
|---|
Because after age two, larger dogs age faster. A giant breed reaches 80 human years by age 10, while a small dog needs 16 years to get there. The first two years are the same for every size: 15 human years at age one, 24 at age two.
Cats use the same first two years (15, then 24) and then add about 4 human years per cat year, whatever the size. Try our cat age calculator for the exact figure.
No — it is a myth. A 10-year-old dog is not 70 in human years: a small dog is about 56, a medium dog about 64, a large dog about 72 and a giant dog about 80.
Dog & Cat Age Calculator — work it forwards from your pet's age.
Dog age by breed: Labrador Retriever · German Shepherd · Golden Retriever