Dog Age Calculator
Dog years in human terms, adjusted for size.
Enter your values
ⓘ Live results
Results
- Human-equivalent age
- 39 years
- Life stage
- Adult
- Typical life expectancy
- 13 years
- Estimated years remaining
- 8 years
- Ageing rate now
- 5 human years per dog year
Quick answer
A dog's first year equals about 15 human years, the second adds 9, and each later year adds 4–6 depending on breed size.
How to use the Dog Age Calculator
- 1Enter your dog's age in years.
- 2Pick the size band by adult weight.
- 3Read the human-equivalent age and life stage.
Worked example
Using the values the calculator loads with:
Inputs
- Dog's age5 years
- SizeMedium (10–25 kg)
Results
- Human-equivalent age39 years
- Life stageAdult
- Typical life expectancy13 years
- Estimated years remaining8 years
- Ageing rate now5 human years per dog year
Frequently asked questions
Is one dog year really seven human years?
No. That rule of thumb badly misrepresents puppies, who mature very fast, and large breeds, who age faster later.
Why do big dogs age faster?
Rapid growth and higher cell turnover shorten lifespan — a Great Dane is geriatric at 7, a Chihuahua barely middle-aged.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.