How this calculator works
Dogs mature much faster than humans in their first two years, then aging slows down — and the rate depends heavily on adult size. Larger breeds age faster in their senior years than small breeds. This tool uses commonly cited veterinary size-based aging curves instead of the oversimplified "1 dog year = 7 human years" rule.
General guide by size
- Small breeds (Chihuahua, Yorkie): age slower after year two, often living 14–16 years.
- Medium breeds (Beagle, Cocker Spaniel): moderate aging pace, typically 12–14 years lifespan.
- Large breeds (Labrador, German Shepherd): age faster after year five, typically 10–13 years lifespan.
- Giant breeds (Great Dane, Mastiff): age fastest, typically 7–10 years lifespan.
This tool is for general information only and isn't a substitute for veterinary advice about your specific dog's health.