Dog Age Calculator
Convert your dog's age to human-equivalent years using logarithmic and linear formulas. Includes size-adjusted estimates.
years
Dog Size
Human Equivalent Age
Logarithmic Method (research)
46.1 human years
Linear Method
28 human years
Log (unadjusted)
48.6 human years
Dog-Human Age Milestones
Puppy (~6 months old)
≈ 7.5 human years
Adolescent (1 year old)
≈ 15 human years
Young Adult (3 years old)
≈ 28 human years
Mature Adult (7 years old)
≈ 44 human years
Senior (10 years old)
≈ 56 human years
Geriatric (15 years old)
≈ 76 human years
How is Dog Age Calculated?
The old "1 human year = 7 dog years" is a myth. Modern research shows dogs age rapidly in their first two years, then slow down. The most cited formula is: Human Years = 16 × ln(Dog Years) + 31. Size also matters — smaller dogs tend to live longer and age more slowly.
Linear: Year 1 = 15 human, Year 2 = +9, then +4 per year
Example
A 3-year-old dog: the linear method gives 24 + (3−2)×4 = 28 human years. The logarithmic method gives 16 × ln(3) + 31 ≈ 48.6 human years. A medium-size dog would be about 46.
Common Use Cases
- Understanding your dog's life stage for health and dietary planning.
- Comparing your dog's biological age to human equivalents.
- Planning age-appropriate exercise, nutrition, and vet schedules.
- Fun conversation about your pet's "real" age.
FAQs
Why is the "1 dog year = 7 human years" formula wrong?
Dogs mature much faster than humans in their first two years. A 1-year-old dog is roughly sexually mature (like a 15-year-old human), while a 7-year-old dog is middle-aged. The logarithmic formula better captures this non-linear aging.
How does size affect dog aging?
Research shows smaller breeds tend to live longer than large breeds. A 10-year-old Chihuahua is biologically younger than a 10-year-old Great Dane. The size adjustment applies a multiplier to reflect this.
At what age is a dog considered senior?
Generally, dogs are considered senior around 7 years for medium/large breeds and 10+ years for small breeds. Giant breeds (Great Danes, Saint Bernards) may be considered senior as early as 5–6 years.