When Do Dogs Stop Growing

Behavior October 20, 2022

When Do Dogs Stop Growing

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While there isn’t a single age at which dogs fully stop growing, most are done by the time they are 12 to 18 months old. However, it can take longer for some larger-size breeds to finish growing while other breeds may get there by month 6.

In this article, we will discuss some general guidelines for when your pup will be fully grown. This can help you get a sense of when you can expect your dog to stop growing.

When Does a Puppy Become an Adult Dog?

Your dog will go through many stages from puppy to adult, but the transition happens much more quickly with dogs than humans.

The most rapid growth can be seen during the puppy stage and slows down at around six to nine months old, depending on the breed and size of the dog.

While it’s hard to believe that your adorable puppy will one day be a full-grown dog, there are three main factors to help you determine when your puppy will stop growing.

  • Breed
  • Sex
  • Other genetic factors

Maturity Stages in Growing Pups

To get a better understanding of what your pup’s maturity growth looks like here is a more in-depth description. This includes their emotional growth as well as their physical development, which usually occurs at the same time.

  • Sexual Maturity – Most dogs become sexually mature at 6 months when they are still considered a puppy both physically and emotionally. At this stage, your puppy’s sex organs are fully developed, which makes them able to reproduce. It is recommended you spay or neuter your pup around this time to avoid unwanted pregnancies and behavioral issues like marking territories or roaming. You are maybe able to spay or neuter at as young as 8 weeks but consult your veterinarian to determine the best age for your pup’s personal needs.
  • Emotional Maturity – When your puppy stops acting like a puppy you will know they are now moving onto an adolescent and then onto the stage of an adult dog. Emotionally mature dogs are much better at listening and obeying, have a calmer demeanor, and are less unruly. Most dogs reach emotional maturity by their second birthday but this can vary for several reasons.
  • Physical Maturity – Dogs are physically fully grown by the time they reach a  year old, but some large breeds will continue to grow until they are 2 years old. While your pup may still act like a puppy, their physical needs, including the number of calories they need and how much exercise they need to stay healthy, must still be met as an adult dog.

How Dog Breeds Sizes Develop

Dog maturation varies based on different breed sizes. Here is some general information based on the size of a dog.

Small Breed Dogs

Small breed dogs are considered those under 25 pounds as fully grown dogs. Small breed dogs usually start growing quickly at 4-6 months and reach their full size between 10-12 months.

These small dog breeds can include Dachshund, Toy Poodle, Maltese, Yorkshire Terrier, Chihuahua, and Bichon Frisé.

Medium Breed Dogs

Medium dog breeds are those that weigh between 22 and 50 pounds as adult dogs. These medium size dogs usually stop growing between 8 to 12 months and are said to double their size during this period.

Medium breed dogs are usually between 25 to 50 pounds when fully grown. Medium breeds include Beagles, Basset Hounds, and Miniature Schnauzers.

Large Breed Dogs

Large dog breeds should reach a weight of 50 to 100 pounds as adults, and stop growing at about 10 to 16 months. Large breed dogs will also double their size at between 8 to 12 weeks, but then the growth slows. These large breed dogs will normally be considered fully grown at 18 months.

Large breed dogs include breeds like Labrador Retrievers, Boxers, Pit Bulls, Golden Retrievers, German Shepherds, and Collies.

Giant Breed Dogs

Giant dog breeds stop growing at around 10 to 16 months. These dogs will be fully grown by 18-24 months but could take up to three years to reach their full weight. Giant dog breeds take the longest to develop, due to their huge skeletal frame.

Giant breed dogs include  Saint Bernard, Great Dane, Mastiff, and Great Pyrenees. These breeds are anywhere from 100 pounds to more than 200 pounds when fully grown.

Male vs. Female Growth

Male and female puppies that come from the same breed will grow at a similar pace and they will stop growing around the same time. However, females will normally end up being smaller than males.

Purebred pups that are born into the same litter and with both sexes will even vary somewhat in size. Size variance may be even bigger in mixed-breed litters because they carry the DNA of different breeds.

What You Can Do to Help Your Puppy Grow Properly

The best thing you can do is to assist with growth by offering a nutritious diet consisting of puppy food that is specifically designed for the dietary needs of your dogs life stage and breed.

Always buy high-quality food that is appropriate for your pup’s age and breed. The wrong diet can lead to your dog becoming overweight, which can then lead to serious health issues as the dog grows.

Exercise is very important in helping your pup stay healthy as he develops. However, strenuous or extensive exercise is not always good for a growing dog because their bones and joints are still developing. This makes them more susceptible to injuries when playing hard.

Why Some Dogs Grow Slower

Your pup needs the right amounts of certain nutrients and protein, or their development can be affected. Small breed dogs stop growing much quicker than larger breed dogs. Larger breeds need more time to reach maturity as opposed to their smaller counterparts because it takes much longer to convert food into new tissue.

Also, a dog’s genetic makeup in different breeds means they will mature at different rates. Not only do larger breeds tend to mature at slower rates than smaller ones but certain breeds can carry genetic markers for conditions that appear as stunted growth like pituitary dwarfism which occurs in German Shepherds.

As a general rule of thumb, smaller dog breeds stop growing when they are around six to eight months old, while larger dog breeds may stop around twelve to eighteen months.

What if Your Dog Has Stunted Growth

If your dog appears to have stopped growing and has not reached the breed’s standard size, it is a good idea to see your veterinarian. Your pup’s breed will be a huge factor, as well as any genetic issues that may be present.

Your veterinarian will most likely discuss proper nutrition for your puppy or may suggest a change to be sure they are getting the correct amounts of proteins and calories for optimal development. As we have mentioned, some dogs grow differently than others due to their breed, but others may have a health condition that can be treated if caught early on.

Final Thoughts

Bringing home a new puppy can be such an exciting time and tracking your dog’s growth through its development stages can be equally fun. However, your dog’s breed is a huge factor that determines how fast or slow he will grow. Feed your puppy a high-quality diet that is appropriate for their stage and see your vet if you have any concerns with his growth.

Woman scratching dog under chin

Amy Brown - Towry is a Certified NAVC Pet Nutritionist and pet lover. She is the proud owner of two rescue cats and a rescue dog and her love for animals has led her to a successful career as a freelance writer specializing in pet care, nutrition, and product reviews.
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