American Staffordshire Terrier Size Guide: How Big Does a Staffie Get?

Also known as AmStaffs and American Staffies, American Staffordshire Terriers have been gaining in popularity as people start to understand that their aggressive reputation stems simply from lousy ownership. In fact, AmStaffs are loyal, playful dogs who love to be around people. 

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.

Most people compare Staffies to the slightly larger American Pit Bull, and they do share many similarities. However, these two dogs have been bred separately for more than 50 years and so are considered distinct breeds. If you have adopted one of these pups, you may be wondering how big American Staffordshire Terriers get. 

American Staffordshire Terrier Size Predictions by Age

Confident, smart, and good-natured American Staffies are medium-sized, muscular dogs that require a lot of loving attention. Their slightly stubborn and dominant nature means that they are probably not a good pick for a novice owner. They need quite a firm hand, are very strong, and can be a little aggressive towards other dogs.

However, with the right person, AmStaffs make excellent pets. They are intelligent and eager to please those they love, which makes them highly trainable. Beyond that, they are total family dogs who just want to be around people as much as possible – preferably while out and about getting plenty of exercise and mental stimulation.

Generally speaking, American Staffordshire Terriers are classified as medium-sized dogs. Still, they are extremely stocky, usually weighing more than Pit Bulls despite being smaller. Let’s take a closer look at their potential adult size and how quickly they get there: 

Age	3 months	6 months	1 year	Adult
Weight	23 – 32 lbs	40 – 59 lbs	40 – 70 lbs	40 – 70 lbs
Height	8 – 10 inches	15 – 18 inches	16 – 19 inches	17 – 19 inches

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

American Staffies do a fair bit of growing in the first three months of their lives, reaching half their adult height, but only around 30% of their adult weight. By the time they get to 6 months, though, you should have a fair idea of your pup’s mature size as they will be about 85% of their full height and 70% of their total weight by then. Although AmStaffs have usually achieved their adult height by 12 months, they will continue to increase in weight until they are somewhere between 16 and 19 months.

Are There Different Sizes of American Staffordshire Terrier?

There tends to be some slight size variations between the males and females of this breed, with males often being 18 to 19 inches and 60 to 70 pounds while females are 17 to 18 inches and 40 to 50 pounds.

While there are no official tiny or teacup versions of these dogs, there is another very similar breed called the Staffordshire Bull Terrier. These dogs are slightly smaller at 14 to 16 inches and significantly less bulky 24 to 38 pounds.

Beyond that, Staffies are closely related to many other ‘Pit Bull’ breeds such as Bull terriers, Bulldog, Miniature Bull Terrier, Boxer. Many of these have smaller versions known as ‘Pocket Pitbulls,’ which are around 10 and 16 inches tall and weigh somewhere between 10 to 30 pounds.

American Staffordshire Terrier Growth Patterns

As with most other dogs, American Staffies get to around three-quarters of their adult size by the time they are 6 months old. After this, their growth slows significantly. Usually, they will get to their adult height around their first birthday but will continue to increase in muscle mass much beyond that. Their mature weight will depend on their diet and activity levels as much as their genetics.

How Big is a Full-Grown American Staffordshire Terrier?

An adult American Staffordshire Terrier will be around 17 to 19 inches and weigh between 40 to 70 pounds. Their specific height and weight will vary based on their gender and how large the parent dogs were – as well as nutrition and lifestyle (as covered above). Male dogs tend to be on the larger side compared to their female counterparts.

American Staffordshire Terriers 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:

What Age is an American Staffordshire Terrier Fully Grown By?

While your AmStaff will likely be at their full height by 12 months old, they are not considered fully grown until they reach both their adult height and weight. Dogs generally always continue to increase in weight beyond this time as they gain muscle mass. This is particularly the case for stocky dogs such as the Staffy. Canine experts would consider one of these dogs to be at their full size by the time they hit 19 months (just over a year and a half).

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While American Staffordshire Terriers make excellent pets for the right kind of family, there are a few things to consider. Firstly, they need firm and consistent training from an early age. Secondly, they often don’t do so well around other animals because of their fighting dog heritage.

You might also be concerned about your AmStaff puppy’s potential adult size. While it’s always best to have a nice big yard for these active pups, they are actually medium-sized dogs and do well even in smaller homes. If you do have room for one of these delightful pooches in your home and in your heart, you won’t be sorry.