Dog Years Calculator

No, the old 7-year rule is oversimplified. Dogs age much faster in their first two years (reaching adolescence by year 1 and maturity by year 2), then the rate varies by size. Smaller dogs age about 4 human years per dog year after maturity, while giant breeds age 6-7 years per dog year.

Larger dogs age faster at the cellular level and face earlier onset of age-related diseases. Scientists believe this relates to accelerated growth rates—large breeds grow from puppy to adult size much faster, which may cause earlier tissue damage and shorter lifespans.

It depends on size. Small dogs become seniors around 10-11 years, medium dogs around 8-9 years, large dogs around 6-7 years, and giant breeds as early as 5-6 years. This is when age-related health screenings become especially important.

The first year equals about 15 human years, the second year adds another 9 years (bringing them to 24). After that, add 4-7 years per dog year depending on size: small dogs add ~4 years, medium ~5, large ~6, and giant breeds ~7 per year.

Mixed breeds often benefit from genetic diversity and may live slightly longer than purebreds, but size remains the primary factor in aging rate. A 30-pound mixed breed will age similarly to a 30-pound purebred, though mixed breeds tend to have fewer breed-specific health issues.