Dog Age Calculator

Convert dog years to human years the way vets actually do it — adjusted for your dog's size. Updated for 2026.

Last reviewed July 2026 · Free · Nothing you enter is stored

Dog's age (years) i

Size class i

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Educational estimate. Individual dogs age differently based on genetics, weight, and health — your vet is the best guide to your dog's life stage.

Find your breed for a size-accurate result

Aging speed tracks body size, so picking your exact breed sharpens the estimate and shows typical life expectancy:

Frequently asked questions

How do you calculate a dog's age in human years?

Not by multiplying by 7 — that myth is long debunked. The veterinary convention counts the first year as ~15 human years, the second as ~9 more (so a 2-year-old dog ≈ 24), then adds 4–6.5 human years per year after that depending on the dog's size. Larger dogs age faster in the later years.

What is the UCSD dog age formula?

A 2020 study derived human_age = 16 × ln(dog_age) + 31 from DNA methylation in Labrador Retrievers. It captures the very fast aging of puppyhood well, but because it came from one breed it can over- or under-estimate for toy and giant breeds. We show it alongside the size-based convention so you can compare.

Do big dogs really age faster?

Yes. A Great Dane is geriatric by 6–7; many small terriers are still spry at 14. That's why our calculator lets you pick a size or breed — the per-year human-equivalent after age 2 rises from about 4 years for toy breeds to 6.5 for giants.

Dog Age Calculator

Find your breed for a size-accurate result

Frequently asked questions

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