Calculators
Dog Age Calculator
Convert a dog age in years and months to human years with a life stage locally in your browser.
Enter your dog's age in years and extra months. Uses first year = 15 human years, second year = +9 (24 total), each year after that = +5. The calculation runs locally in your browser; your values are not uploaded or stored.
Find a dog age in human years without uploading anything.
Enter your dog's age in years and extra months to see the human-age equivalent and life stage with the formula shown. Everything runs locally in your browser, so your values are not uploaded or stored.
Frequently Asked Questions
Everything you need to know about this tool, how it works, and privacy.
What does the dog age calculator show?
Enter your dog's age in years from 0 to 25 plus optional extra months from 0 to 11. The calculator returns the human-age equivalent and the life stage from puppy to geriatric with the calculation shown. For example, a 4-year-old dog maps to about 34 human years and the Adult stage.
Which formula does the dog age calculator use?
It uses the common veterinary rule of thumb: the first year equals 15 human years, the second year adds 9 (24 total), and each year after that adds 5. Ages under one year scale linearly within the first year, so a 6-month-old puppy maps to about 7.5 human years. Real ageing varies by breed, size, and health, so treat the result as an estimate.
Which inputs are accepted?
Enter whole-number dog years from 0 to 25 and whole-number extra months from 0 to 11; the months field may be left blank for 0. The total age must be greater than zero and no more than 25 years. Puppies under one month can be entered as 0 years and 1 month. Missing years, fractional values, non-numeric text, and values outside these ranges show a clear error instead of a result.
Do my values stay private?
Yes. The calculation and copy action run locally in your browser. CodeASystem does not upload or store the values you enter.