Dog Age Calculator

Convert your dog's age to human years, adjusted for size.

Age in human years

39years

First year counts as: 15 yrs
Second year adds: 9 yrs
Each year after adds: 5 yrs

Age in human years39

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How it works

The old "multiply by 7" rule is a myth. Dogs mature fast in their first two years (about 24 human years), then age 4–7 human years per year depending on size — bigger dogs age faster.

Formula

Year 1 = 15 · Year 2 = +9 · Each later year = +4 to +7 by size

Example

A 5-year-old medium dog is about 24 + 3 × 5 = 39 in human years.

Assumptions & limitations

Results are rounded for display.

Frequently asked questions

Is this exact?

No — it's a widely used veterinary rule of thumb. Breed and health matter too.