Dog Age Calculator
Convert your dog's age to human years with the modern UC San Diego formula, a breed-size table or the classic 1:7 rule. Runs privately in your browser.
๐ Runs entirely in your browser โ nothing is uploadedHow dog years become human years
For decades people multiplied a dog's age by seven to get a human equivalent. It is easy to remember, but it is wrong at both ends: a one-year-old dog is closer to a teenager than a seven-year-old child, and a ten-year-old dog is not seventy. Dogs mature quickly during their first two years and then age more slowly, at a pace that depends heavily on body size. This calculator offers three methods so you can compare them for your own dog.
The three methods explained
The modern formula comes from a 2019 UC San Diego study that compared DNA methylation in dogs and humans. It gives human age โ 16 ร ln(dog age) + 31, so a 5-year-old dog is about 57 human years. The breed-size method follows the common veterinary table: 15 human years for the first dog year, 9 more for the second, and then 4 (small), 5 (medium), 6 (large) or 8 (giant) years for every year after that. The classic rule simply multiplies by seven and is included for reference.
Life stages and what they mean
Besides the human-age equivalent, the tool labels your dog as a puppy, adult, mature adult or senior. Small dogs are usually considered senior from about 10 years, medium dogs from 9, large dogs from 7 and giant breeds from 6. Senior pets benefit from more frequent vet visits, joint care, dental checks and diets adjusted for lower activity.
Remember that every dog is an individual. Genetics, diet, exercise and healthcare all influence how a dog ages, so use the result as a friendly guide rather than a medical fact. Nothing you enter leaves your browser.
How to use
- Enter your dog's ageType the age in years and extra months. A 5-year-6-month-old dog is 5 years and 6 months.
- Choose a methodPick the modern UC San Diego formula, a breed-size table, or the classic 1 : 7 rule.
- Select the breed sizeChoose small, medium, large or giant. Size drives the life stage and the breed-size method; then read the human-year equivalent.