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When Do Pitbulls Stop Growing? Average Breed Size & Determining Factors

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By Nicole Cosgrove

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Knowing how big your new puppy will grow to be is an important consideration, especially if you have limited space at home or can’t afford to care for a big dog. Most Pit Bulls are medium-sized dogs with plenty of muscle and will only stop growing when they’re between 12 and 18 months old. Since they’re not classed as a breed of their own, their final size and growth rate can vary.

This guide will explain more about these dogs and how big they are when they finish growing, so you can decide whether a puppy of this type is ideal for your family.

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What Are Pit Bulls?

Although many people recognize the Pit Bull, they’re not a breed of their own and haven’t been recognized by the American Kennel Club (AKC). Instead, the term is used for dogs of mixed heritage that have certain traits, such as muscular bodies and broad heads.

American bully enjoying the sun in a field
Image Credit: Glenn Van Bergen, Shutterstock

Historically, the term described the Bulldogs and Terriers used as fighting dogs in Scotland during the 19th century. As a result, “Pit Bull” is commonly used to refer to any one of four dog breeds:

While the Pit Bull isn’t seen as an actual breed by many organizations, they are recognized by the United Kennel Club (UKC) and the American Dog Breeders Association (ADBA). The UKC recognized the American Pit Bull Terrier in 1898, and the ADBA is dedicated to spreading awareness of the breed’s loyalty, athleticism, and dedication in order to break down the negative reputation that these dogs have.

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How Big Are Adult Pit Bulls?

Since the term “Pit Bull” usually refers to several breeds rather than just the American Pit Bull Terrier, their size and when they stop growing can vary. There are four different breeds of Pit Bull-type dogs, and they each grow at different rates.

American Bully

American bully enjoying the sun in a field
Image Credit: gonzalo vidania, Shutterstock
Adult Male 17–20 inches, 50–70 pounds
Adult Female: 16–19 inches, 40–60 pounds
Age Growth Stops: 12–18 months

Bred to be a companion dog, the American Bully was developed from the American Pit Bull Terrier. Due to the differences in body structure, the American Bully quickly became recognized as a separate breed by the UKC. However, this breed, like the American Pit Bull Terrier, is not recognized by the AKC.

American Pit Bull Terrier

Image Credit: Anna Krivitskaya, Shutterstock
Adult Male 18–21 inches, 35–60 pounds
Adult Female: 17–20 inches, 30–50 pounds
Age Growth Stops: 18 months

Despite the Pit Bull—or Pit Bull-type dogs—being familiar to many dog owners, the American Pit Bull Terrier isn’t classed as a breed by the AKC. The standard height and weight of the American Pit Bull Terrier are standardized by the UKC instead. Like other Pit Bull breeds, the American Pit Bull Terrier originated in 19th-century England from the Bulldogs and Terriers used in bullfights.

American Staffordshire Terrier

American Staffordshire Terrier on mulch_Shutterstock_Tom Myers
Image Credit: Tom Myers, Shutterstock
Adult Male 18–19 inches, 55–70 pounds
Adult Female: 17–18 inches, 40–55 pounds
Age Growth Stops: 12–18 months

A Pit Bull-type of dog that is recognized by the AKC and considered an actual breed is the American Staffordshire Terrier. As with all Pit Bull breeds, these dogs got their start in the bull-fighting rings of 19th-century England. Also known as the AmStaff, the American Staffordshire Terrier was a larger, American-bred version of the English Staffordshire Bull Terrier.

Staffordshire Bull Terrier

staffordshire bull terrier stretching
Image Credit: Melounix, Shutterstock
Adult Male 14–16 inches, 28–38 pounds
Adult Female: 14–16 inches, 24–34 pounds
Age Growth Stops: 12–18 months

Perfected by James Hinks in Birmingham, England, in the mid-19th century, the Staffordshire Bull Terrier is the smallest of the four Pit Bulls that we know today. They’ve been around longer than the American Staffordshire Terrier but were only recognized as a separate breed by the AKC in 1974, 38 years after their American descendants.

Divider 5How to Estimate the Size of Your Pit Bull

Since there is so much variety in Pit Bull breeds, knowing how big your Pit Bull will be isn’t always possible. Fortunately, there are a few ways that you can tell whether your Pit Bull puppy still has growing to do.

Consider Their Age

The easiest way to tell if your Pit Bull still has to grow is by considering their age. It might be difficult to know your adopted puppy’s age for certain, but even a rough estimate of how old they are can help you.

Most Pit Bull breeds are fully grown once they hit 12 months old, though many of them keep growing until they’re 18 months old. After the 18-month mark, your puppy’s height will stay the same.

Ask the Breeder

Genetics significantly affect how big your puppy will grow to be and how long it’ll take them to reach adulthood. Some dogs mature faster than others, and the breed and your puppy’s parents can play a big part in how your dog grows.

If you’re not sure what size your dog will be when they stop growing, ask the breeder you purchased your dog from. They’ll be able to give you an estimated size based on what they know about the parents and other puppies born to them.

Check Their Paws

For adopted puppies, you won’t have a breeder to ask and might not even know their true age, especially if they’re almost adults when you adopt them. In this case, take a look at your Pit Bull’s paws in comparison to the rest of their body.

Pit Bulls that still have a bit of growing to do often look like they have oversized feet. This is a good sign that their body needs to fill out more before they stop growing.

Dog paws
Image Credit: LUM3N, Pixabay

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What Factors Affect the Size of Your Pit Bull?

Since the term “Pit Bull” generally refers to dogs with the iconic broad head and muscled body rather than a breed, there is no standard size for Pit Bulls. Instead, the final size of your Pit Bull puppy depends on a few other important factors.

Activity Level and Diet

Two factors that you can control are their diet and how much your dog exercises. Your Pit Bull will likely stop growing when they’re between 12– and 8 months old. Once they’re an adult, only their weight will change depending on how much exercise they get and the food they eat.

The more your dog eats and the less active they are, the more likely they are to gain weight. However, if you feed them a balanced diet and take your Pit Bull for regular walks and play together often, they’ll stay at a healthy weight.


There isn’t much of a noticeable difference between male and female Pit Bulls, but sex is still a crucial factor when it comes to the adult size of your puppy. Male dogs—regardless of their breed—are usually larger than females by at least a few inches. They’re also likely to weigh more.

What is a Blue Fawn Pit Bull
Image Credit By: stardust_and_diamond, instagram

Genetics and Sub Breed

How big the parents are will determine how big your puppy will be as an adult. It’s one of the reasons that you should ask the breeder for an estimate of how big your puppy will be.

The breed of your Pit Bull makes a difference too. Each of the four breeds classed as Pit Bulls ranges in size when fully grown. This in turn, makes a difference in how fast your dog will grow and how big they’ll be when they’re an adult. For example, a Staffordshire Bull Terrier will grow to be smaller than an American Pit Bull Terrier, but a mixed breed might be anywhere between the two.

Neutering and Spaying

Hormonal changes play a part in your Pit Bull’s size too. Dogs should be spayed once they’re fully grown, which can be anywhere between 9 and 15 months old. This gives a medium-sized Pit Bull plenty of time to benefit from their hormones as they grow. If they’re spayed too early, the change of hormones can interfere with their growth.

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Pit Bulls aren’t recognized as a breed of their own by the AKC. Instead, the term refers to a variety of Bulldog and Terrier breeds developed during 19th-century England for bullfighting. Due to the lack of a standard for the breed, Pit Bulls can range in size when they’re adults. Most Pit Bulls will finish growing when they’re 1 year old, while some puppies grow slower and only finish growing when they’re 18 months old.

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Featured Image Credit: Melounix, Shutterstock

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