Convert your dog's age to human years using the latest veterinary science. Results account for your dog's size, since smaller breeds age more slowly than larger ones.
Human-Equivalent Age
~39 years
Life Stage
Adult
Typical Lifespan
10-14 years
Puppy
0-15
Young Adult
15-30
Adult
30-55
Senior
55-75
Geriatric
75-120+
Human-equivalent ages for a medium dog
6 months
~8
human yrs
Puppy
1 year
~15
human yrs
Puppy
2 years
~24
human yrs
Young Adult
5 years
~39
human yrs
Adult
8 years
~54
human yrs
Adult
12 years
~74
human yrs
Senior
Side-by-side comparison showing equivalent life progression
Smaller dogs age more slowly than larger breeds after maturity
Small
<20 lbs
~36
human years
4 yrs/yr after 2
Medium
20-50 lbs
~39
human years
5 yrs/yr after 2
Large
50-90 lbs
~42
human years
6 yrs/yr after 2
Giant
90+ lbs
~45
human years
7 yrs/yr after 2
What to expect and care tips for each life stage
Rapid growth and development. Learning socialization, basic training, and exploring the world.
Peak energy and physical condition. Fully grown but still playful and active.
Mature and settled. May begin to slow down slightly but maintains good health.
Care tip: Monitor weight, annual vet checkups, joint health supplements.
Noticeable slowing. May develop age-related conditions. Still enjoys life with accommodations.
Advanced age requiring extra care, comfort, and attention to quality of life.
Dogs do not age at a constant rate relative to humans. They mature rapidly in their first two years of life, then the aging process slows down. A dog's size plays a significant role — small dogs tend to live longer and age more slowly after reaching maturity, while giant breeds age the fastest. This calculator uses size-adjusted aging rates based on guidelines from the American Veterinary Medical Association.
No, the old "multiply by 7" rule is a myth. Dogs age much faster in their first two years — a 1-year-old dog is roughly equivalent to a 15-year-old human. After age 2, the rate depends on the dog's size, with larger dogs aging faster than smaller ones.
Scientists believe larger dogs age faster because their bodies work harder to grow and maintain more mass, putting greater strain on organs and cellular processes. Large breed dogs also have higher rates of cancer. Small dogs can live 12-16 years, while giant breeds may live only 6-10 years.
It depends on size. Small dogs are generally considered senior around 10-12 years, medium dogs at 8-10 years, large dogs at 7-8 years, and giant breeds as early as 5-6 years. Senior dogs benefit from more frequent vet checkups and adjusted nutrition.
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