How old is my Jack Russell Terrier? The secret 7 dog year lie

If you’re wondering “How old is my Jack Russell Terrier in dog years?” you’ve come to the right place. While it’s common knowledge that one human year is the equivalent to seven dog years, it’s not a blanket rule. In fact it can vary hugely by breed, with some larger dogs only averaging the age of 10 while smaller dogs, like Jack Russell’s, average the grand old age of 15.