Convert your dog This tool processes all data locally in your browser. No information is ever sent to any server. Completely free, no registration required.
A Dog Age Calculator converts between dog years and human years using the latest epigenetic research — not the outdated 'multiply by 7' rule. In 2020, UC San Diego researchers published a landmark study showing that dogs age rapidly in their first two years (reaching the equivalent of ~30 human years by age 2) and then slow to ~5-7 'human years' per dog year depending on breed size. The old 7:1 rule underestimates early aging (a 1-year-old dog is more like a 15-year-old human) and overestimates later aging. Small dogs age slower and live longer; giant breeds age fastest.
Enter your dog's age and select breed size (small <21 lbs, medium 21-50 lbs, large 51-90 lbs, giant >90 lbs). The calculator uses the logarithmic formula from the 2020 UC San Diego epigenetics study for general human-equivalent age, adjusted for breed size. Results show: human age equivalent, life stage (puppy, adolescent, adult, senior, geriatric), remaining estimated lifespan, and key age milestones.
UC San Diego Epigenetic Formula (general):\nHuman Age = 16 × ln(Dog Age) + 31\n\nBreed Size Adjustments:\n• Small (<9 kg/20 lbs): human age estimate −5% per year after year 5\n• Medium (9-23 kg): base formula (most accurate)\n• Large (23-41 kg): +10% per year after year 5\n• Giant (>41 kg): +15-20% per year after year 5\n\nLife Stages:\n• Puppy: 0-1 year (human equiv 0-15)\n• Adolescent: 1-2 years (human equiv 15-30)\n• Adult: 2-7 years (small dogs 2-9)\n• Senior: 7-10 years (small dogs 9-12)\n• Geriatric: 10+ years (small dogs 12+)\n\nOld Rule (inaccurate): Human Age = Dog Age × 7
No. A 1-year-old dog is roughly equivalent to a 15-year-old human (not 7), and a 2-year-old is ~24 (not 14). After year 2, each dog year equals roughly 4-6 human years, varying by breed size. The 7:1 rule significantly underestimates early aging.
The leading theory: larger dogs grow faster (putting more metabolic stress on cells) and have higher levels of IGF-1 (insulin-like growth factor), which is associated with faster aging and higher cancer rates across species. Lower metabolic rates in small dogs may also contribute.
Free online Dog Age Calculator — no signup, 100% client-side processing. All data stays in your browser.