How to Tell How Old Your Dog Is

By: Contributors  | 
old Labrador retriever
Can you really ever figure out how old your dog is if you don't know the exact day it was born? Purple Collar Pet Photography/Getty Images

Knowing how old your dog is can be very important to your pet's health care. Puppies have different needs than adolescent canines, which have different needs than middle aged and older dogs. Dogs age must faster than humans do, and with old age comes increased health problems and risks. If you don't know your dog's age, you can't take care of it properly. Here are a few tips to help you tell how old your dog is:

  • Look at your dog's teeth The best way to guess your dog's age is from the condition of its teeth. Puppies get all their baby teeth in by the time they're about 8 weeks old, and permanent teeth won't start to show up until they're around 3½ months old. All permanent teeth will be in by the time a dog is about 7 months old. These will stay clean and white until the dog's a year old. Up until 3 years old, the teeth will show some dullness and tartar build-up will begin only in the back teeth. From 3 to 5 years of age, all the teeth will show tartar build-up and wear. After your dog is 5 years old, the teeth will look very worn and possibly diseased [source: HSUS].
  • Examine the eyes Older dogs' eyes sometimes develop a hardening of the lens protein and appear cloudy. This condition usually doesn't affect their sight, but does indicate that you should bring your friend to the vet [source: PetMD].
  • Check the fur coloring Some dogs begin to gray when they're about 7 to 10 years old. The muzzle usually turns the grayest [source: PetMD].
  • Pay attention to your dog's hearing If you start to notice that your dog seems to be turning more aggressive or isn't following commands, have its hearing checked. As dogs age they often lose some of their hearing. The dog that seems to be aggressive simply can't hear people approaching and is startled, and the dog that no longer follows commands simply doesn't hear them [source: AKC].

The American Kennel Club has a chart listing your dog's age in human years depending on its size. Smaller dogs tend to live longer than large dogs.


Dog Age FAQ

How old is a 7-year-old dog?
A 7-year-old dog is considered to be in its senior years. In human years, it is somewhere between 44 and 50 years, depending on the size and breed of the dog.
How do you calculate a dog's age?
It used to be said that you take 1 dog year and multiply it by 7. This calculation is based on the assumption that dogs tend to live for about 10 years and humans for 70. However, science does not support this theory, and multiple other factors affect a dog's age. The American Veterinary Medical Association says that the first year is equal to 15 human years, the second year to 9 human years and after that each year is equal to 5 human years.
How old is a 1-year-old dog in human years?
According to the method provided by the American Veterinary Medical Association, a 1 year old dog would be about 15 in human years.
What is the maximum age of a dog?
Determining the age of a dog depends on the dog’s breed and size. It is believed that smaller dogs tend to live for 15 years, large-sized dogs 10 to 12 years, and giant dogs often live up to 7 to 8 years.
How old is a 4-month-old puppy in human years?
At 4 months old, your puppy is probably the same age as your toddler.