Convert a dog’s age and weight into an approximate human-age equivalent using size-adjusted veterinary tables rather than the outdated “multiply by seven” rule.
How size categories work
Weight in kilograms selects a breed-size bucket:
- Small — up to 9 kg
- Medium — 9.1–22.6 kg
- Large — 22.7–45 kg
- Giant — above 45 kg
Each category applies a year-by-year accumulation table. The first year typically counts as 15 human years, the second adds about 9–10, and later years add smaller increments that vary by size — large breeds age faster in human-equivalent terms after middle age.
When to use it
Explain pet aging to owners, illustrate why a 2-year-old Great Dane differs from a 2-year-old Chihuahua in “human years,” or supplement veterinary wellness conversations with a tangible number.
Limitations
Tables are population averages. Individual dogs differ by genetics, neuter status, diet, and chronic disease. The model does not predict lifespan or medical risk — it only maps calendar age to a human-age metaphor.
Health disclaimer
This is not veterinary diagnosis or treatment advice. Wellness screening, vaccination, and nutrition decisions require a licensed veterinarian who knows your dog’s history. Do not delay professional care based on a human-age estimate.