When Will My Puppy Stop Growing?

Kelly Roper
Contributor: Mychelle Blake
Close-up portrait of dalmatian puppy

When do puppies stop growing? That's something many owners would like to know. However, this is a question that has more than one answer.

Dispelling a Generalization

It used to be considered common wisdom that dogs stop growing once they reach one year of age. While that may be a fairly accurate statement in some cases, it does not hold true in others.

This misconception is largely due to the fact that many kibble manufacturers recommend that you only feed puppy kibble until your dog reaches one year of age. However, a puppy does not magically stop growing on the day of its first birthday.

Growth Rates Differ by Breed and Size

If you make a comparison using breeds at both ends of the spectrum, it becomes apparent that all breeds do not grow at the same rate.

For example, compare the Chihuahua and the Great Dane. The Chihuahua will remain relatively small throughout its lifetime, and it doesn't have nearly as far to grow to reach its adult size as a Great Dane puppy does. So, the Chihuahua will likely reach its adult frame and rate closer to one year of age, while the Great Dane will take much longer to fully mature in size.

So, When Do Puppies Stop Growing?

five puppies looking down at camera

Although nutrition and living circumstances play a definite role in when puppies stop growing, each puppy is an individual and may grow at a slightly different rate than other members of its breed or even from its own litter. On average, you will see the fastest growth in puppies in the first four to five months of age. Still, a few generalizations can be applied to dogs that fall into basic size categories of small, medium and large breeds. You can tell the approximate size of your puppy based on breed averages as well.

Small Dogs

Most small dogs will reach their full body frame size by approximately one year of age.

  • For example, the smallest breeds, such as Chihuahuas and Yorkshire terriers will likely reach their ideal adult weight by age one.
  • However, stockier breeds such as the Chinese Pug, Boston Terrier or Shih Tzu may take a couple of months beyond that for their weight to catch up to their frame size.
  • A "medium-sized" small breed with a regular build such as a Bichon Frise should hit his full size at about one year.

Medium Dogs

Husky puppy with toy in mouth

In general, most medium size breeds will reach their full adult frame size between 12 and 15 months old. Breeds with stockier bodies may take as long as 18 months of age for their weight to catch up to their frame size.

  • Whippets and Clumber Spaniels are considered medium-sized breeds, but their body types represent opposite ends of that spectrum. So, the Whippet will most likely stop growing sooner than the Clumber Spaniel.
  • Border Collies will settle into their final size between 12 to 15 months of age.
  • Goldendoodles will reach their full height and weight at about 30 weeks or around 2 to 2-1/2 years.
  • On the taller end of the spectrum, a German Shepherd or American Pit Bull Terrier, which all tend to leaner, athletic builds...

Large Dogs

Large breeds take the longest of all to reach their full size. Their frames typically keep growing until they are between 18 months and 24 months of age while they may be anywhere from 24 to 36 months old before they reach their full adult body weight.

  • An Irish Wolfhound has a large frame, but its body is actually rather lean. By comparison, a Mastiff has a large frame, but a lot more body density and musculature. So, the Wolfhound will likely reach full maturity quicker than the Mastiff.
  • Labrador Retriever puppies will reach their final size around 2 years old although he should reach the majority of his size around 9 months.
  • The tallest dog, the Great Dane can take between two to three years to reach their final height and weight.

A Puppy's Height

Puppies will reach their full height depending on their breed size group.

  • Small and toy breed dogs reach their final height around nine months.
  • Medium breed dogs hit their full height at approximately one year.
  • Large and giant dogs do not hit their final adult height until 18 months to up to two years.

Reaching Adulthood

Like height and weight, a dog can be considered mature based on their size grouping.

  • Small and toy dogs are generally considered out of the puppy stage between nine and 12 months of age.
  • Medium size dogs reach adulthood at about one year of age.
  • Large dogs are considered adults at between 12 to 16 months depending on their size.
  • Giant breed dogs can take as long as 18 to 24 months to no longer be considered in the puppy stage.

How Old Is My Puppy?

Most often adopters from a rescue will bring home dogs where the exact age is not known. If this is the case with your puppy, your veterinarian can look at their teeth to give you a close approximation of their age.

Expectations for Your Own Puppy

As you can see, it's difficult to pinpoint an exact answer to the question "When do puppies stop growing?" The best you can do is compare your own puppy's expected size, based on his breed heritage, to the examples given above. Watch him carefully as he nears adulthood, and you'll eventually notice that he hasn't grown any larger for several months. At that point, it's safe to assume he has finally stopped growing.

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When Will My Puppy Stop Growing?