Is "1 dog year = 7 human years" still accurate?

No — the 1:7 rule is a myth. Dogs mature much faster in their first two years (roughly 15 human years in year one, 9 more in year two), then slow to about 4–5 human years per dog year. Our calculator uses the logarithmic DNA-methylation formula published in 2020 which matches real biological ageing.

Do small and large dogs age at the same rate?

No. Giant breeds reach senior age much sooner than small breeds — a Great Dane may be "senior" at 5 while a Chihuahua is still middle-aged at 10. Our calculator gives a species-level estimate; for breed-specific ageing, speak to your vet.

How do cats age compared to dogs?

Cats age quickly too: a 1-year-old cat is roughly a 15-year-old human and a 2-year-old cat is about 24. After that, every feline year adds about 4 human years. Cats generally outlive dogs, with indoor cats commonly reaching 15–18.

When is my dog a senior?

Most vets label dogs senior from 7 — earlier for giant breeds (5–6) and later for small breeds (8–10). Senior check-ups every 6 months are recommended to catch age-related conditions early.

When is my cat a senior?

AAFP/ISFM guidelines classify cats as "senior" from 11 and "geriatric" from 15. Watch for weight changes, drinking more, and stiff movement — all early signs worth a vet call.

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How old is your pet
in human years?

Based on the standard veterinary formula. Dogs and cats age differently per year — here's what your pet's age really means.

Species

I know my pet's…

Date of birth

How the formula works.

Dogs and cats don't age at a steady 7 years per human year — that's a myth. The widely-accepted veterinary formula is:

Year 1: ≈ 15 human years (puppies and kittens mature fast)
Year 2: adds another 9 (≈ 24 human years total)
Each year after: adds about 4 human years

Small dogs typically live longer than large dogs — a Great Dane at 6 is closer to “senior” than a Chihuahua at 6. This calculator uses averages.

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