How to calculate dog age

Since the life span of a dog is usually limited to 15-20 years, owners need to note that a two-year-old dog is a young dog, a nine-year-old dog is a middle-aged dog, and a fourteen-year-old dog is It is an elderly dog. The general calculation formula is "one year old dog, seven years old human". A dog's first year = 15 years, a dog's second year = 10 years, and each subsequent year of dog age equals 3 years of human age.
Owners note that small dogs or teacup dogs: do not start to age until they are 10 years old. Large dogs: start to age after 5 years old. After the third year of dog life, the dog age of small and medium-sized dogs is approximately: 1 natural year = 5 years of dog age; the dog age of large and giant dogs is approximately: 1 natural year = 6-7 years of dog age.