American Bulldog Size Guide: How Big Does an American Bulldog Get?

American Bulldogs are classified as a large breed, and all that muscle can make them mighty pups. You need to be fully prepared for what you are getting yourself into when adopting one of these darling dogs. The first question you might have is: what is an American Bulldog size and exactly how large do they get? This article will detail the height and weight details of the breed, take a look at growth patterns and generally just help you understand a bit more about your American Bulldog puppy.

Our handy interactive puppy growth chart and calculator takes all the hard work out of predicting your puppy’s potential adult size. This helps you to know exactly what you are in for.

American Bulldog Size Predictions by Age 

Stocky and muscular, yet quick and agile, American Bulldogs are very special canines indeed. They make incredibly loyal companions for the right owner, as well as excellent watchdogs and great all-around working dogs.  With a bit of care, a little training, and a lot of attention, they can fit right into almost any home. 

Loving, energetic, intelligent, American Bulldogs are a descendent of English Bulldogs. These dogs were bred to do different jobs around the farm. They were also sadly used in the blood sport bull baiting – which is how they got their name.

A misconception about the breed is that they are vicious, aggressive dogs. In actual fact, they are very affectionate, people-loving pooches. However, their high exercise needs, coupled with their strong prey drive and wariness of strangers (both people and dogs), means that this is not the best breed for a novice owner.

If you do take on one of these pups, you will need to be hot on both training and socialization. As working dogs ABs pick up new commands and tricks with ease through positive reinforcement. They don’t respond well to shouting, hitting, or any other forms of punishment. Yet with the right kind of encouragement, they are beautifully responsive and obedient canines.

In terms of size, these dogs grow pretty rapidly, especially in the first few months, as can be seen below:

Age	3 months	6 months	1 year	Adult
Weight	25 – 43 lbs	40 – 75 lbs	55 – 110 lbs	55 – 125 lbs
Height	12 – 16 inches	18 – 22 inches	20 – 27 inches	20 – 27 inches

*A dog’s height is measured from its withers – this is the point between the shoulder blades.

At 3 months old, the American Bulldog is already at around 50-60% of their adult height. By 6 months, they are just about there. It takes a little longer for them to reach their mature weight. They are considered fully grown at 18 months.

Are There Different Sizes of American Bulldog?

Mostly named for the breeders who created them, there are said to be four distinct varieties of American Bulldog today, and yes, they are slightly different sizes.

• The Johnson American Bulldog, also known as the ‘Bully’ or ‘Classic’ American Bulldog, are the larger ones. Both taller (23 to 27 inches) and more muscular (up to 120 pounds), they most closely resemble their cousin pups, the English Bulldog.
• The Scott American Bulldogs, also known as the ‘Performance’ or ‘Standard’ American Bulldogs, are smaller (22 to 25 inches and up to 100 pounds) but much more agile and athletic. They have longer muzzles and are more leanly built than the Johnson dogs.
• The Painter American Bulldog was unfortunately created exclusively for fighting purposes. These dogs are around the same height as the other two but much lighter (55 to 75 pounds). Their breeding was poorly done initially, but responsible facilities are now working on healthier dogs with better temperaments.
• The Old Southern White American Bulldogs, also known as White English Bulldogs, have been around longer than any of the others. They are said to be the true American Bulldogs. Again, they are a little smaller than the first two types at 21 to 26 inches and 60 to 97 pounds.

Aside from these, there are various hybrid American Bulldogs that are a combination of two or more of the above. It can be tricky to predict the exact measurements of these dogs are genetics are complicated. However, the size difference – especially in terms of height – isn’t really all that profound. 

There also tend to be gender differences with these dogs, as is the case with larger, more muscular breeds. Females weigh 60 to 80 pounds and stand between 20 and 23 inches high. Males weigh 75 to 100 pounds and are around 22 to 25 inches in height.

American Bulldog Growth Patterns

By the time these dogs are six months old, they are already close to their adult height. They will often reach this somewhere between 9 and 12 months but will continue to put on weight significantly into their first year. 

As large dogs, ABs are said to be at their mature size at around 18 months. Still, realistically male dogs on the larger end of the spectrum could continue to gain muscle mass right up to their second birthday and even beyond this.

How Big is a Full-Grown American Bulldog?

Depending on their gender, their parents, and the kind of lifestyle they have (working dog, active companion, family dog), an adult American Bulldog will be around 20 to 27 inches to the shoulder and will weigh somewhere between 55 to 125 pounds. They are categorized as a large breed. 

American Bulldogs usually get to half their total weight around 4 – 5 months and their adult size at roughly 18 months. 

A different formula you could use is:

1. Growth = current weight / current age in weeks
2. Adult weight = Growth x 52 (number of weeks in one year)

So, for example, if your 12-week old pup weighs 18 pounds. You simply divide the current weight by their age in weeks and multiply the result with 52:

At What Age is an American Bulldog Fully Grown?

Large dogs are said to be fully grown at around 18 months of age. They will often achieve their mature height somewhat earlier than that at between 9 months to 12 months, depending on whether they are destined to be smaller or larger pups. However, they will continue to gain weight as their muscles develop for quite a while after this. This will especially be the case if they are getting plenty of exercise. You shouldn’t expect to notice any dramatic changes in your dog’s height after their first birthday, though. 

Look to the parent dogs for clues on what you might expect in terms of your pup’s final size. Genetics provides the best understanding we have on this. Otherwise, you can tap your puppy’s numbers into our handy interactive puppy size calculator to get a reasonably accurate guesstimate. 

American Bulldogs are gaining a better reputation these days as fun and friendly family dogs. They are especially beloved by particularly active individuals looking for a little company on their walks, hikes, runs, etc. If you’re looking to get one of these precious pups, then you might have a few concerns about their size. Hopefully, this article has been able to address these, and you have a fair understanding of what to expect from your (future) puppy.