Free calculator

Dog age calculator: dog years to human years

Convert your dog’s age into human years with a size-aware formula, and see when your dog counts as a senior.

YearsMonths

Adult size

Enter your dog’s age.

Why times seven is wrong

A one year old dog is already sexually mature and nearly full grown, which is much closer to a human teenager than a seven year old child. Most estimates put the first year at around 15 human years and the second at about 9 more.

After that, size takes over. Small dogs tend to age about four human years for each calendar year, while giant breeds age closer to seven. That is why a 10 year old Chihuahua can be spry while a 10 year old Great Dane is very elderly.

Using the result

Senior age is a useful planning point: it is when many vets suggest twice-yearly checkups, a look at diet and weight, and small changes at home such as better grip on floors and a raised bowl for stiff necks. The exact human-age number is an approximation, so treat it as a conversation starter rather than a medical fact.

Questions about this tool

When is my dog a senior?

Roughly from 9 to 10 years for small dogs, 8 for medium, 7 for large and 6 for giant breeds. Individual health matters more than the calendar.

Is there a more accurate method?

Researchers have proposed formulas based on DNA changes, but they were built on a single breed. Size-based estimates remain the most practical for everyday use.