If you are thinking about bringing an American Bulldog into your home -- or you already have one and want to know what to expect -- size matters. American Bulldogs are a large, powerful breed with real variation depending on bloodline and type. This guide breaks down everything you need to know about how big American Bulldogs get, from puppyhood through adulthood.
American Bulldog Size by Type
Not all American Bulldogs are built the same. The breed has distinct types that influence adult size and build. Understanding these differences helps set realistic expectations for your dog's growth.
Johnson (Bully) Type
The Johnson type -- also called the Bully or Classic type -- is the stockier, heavier version of the breed. These dogs have wider chests, thicker bones, and more mass overall. Males often weigh 90 to 120 pounds, and some well-built males push past that range. Females typically land between 70 and 90 pounds. Johnson types have a broader head and a shorter muzzle compared to other lines. If you want to understand how this type differs from the Standard, check out our Scott vs. Johnson American Bulldog comparison.
Scott (Standard) Type
The Scott type -- also called the Standard or Performance type -- is leaner and more athletic. These dogs are built for speed and endurance rather than raw bulk. Males generally weigh 70 to 100 pounds, and females weigh 60 to 80 pounds. They stand slightly taller in proportion to their weight, with a longer muzzle and a more streamlined frame.
Hybrid Type
Many modern American Bulldogs are a cross between Johnson and Scott lines. Hybrid dogs fall somewhere in the middle on both size and build. A hybrid male might weigh 80 to 110 pounds depending on which parent's traits dominate. This blending of types is common in working lines and well-rounded family dogs alike.
American Bulldog Growth Timeline
Puppies grow fast. The table below gives you a general idea of what to expect at each stage. Keep in mind that individual dogs vary -- these are averages across the breed.
| Age | Male Weight (lbs) | Female Weight (lbs) |
|---|---|---|
| 3 months | 25 -- 40 | 20 -- 35 |
| 6 months | 45 -- 65 | 35 -- 55 |
| 9 months | 60 -- 85 | 50 -- 70 |
| 12 months | 70 -- 100 | 55 -- 80 |
| 18 months | 75 -- 110 | 58 -- 85 |
| 24 months | 75 -- 120 | 60 -- 90 |
If your puppy seems smaller or larger than these ranges, do not panic. Genetics play a huge role, and some dogs are simply late bloomers. If you have concerns about your pup's growth, a vet checkup is always a good call.
Want a projection for your own pup? Use our American Bulldog growth chart and weight calculator to estimate adult weight from age, sex, and type.
When Do American Bulldogs Stop Growing?
Most American Bulldogs reach their full height by 12 to 14 months of age. But height is only half the story. These dogs continue to fill out -- adding muscle, chest depth, and overall mass -- until they are 2 to 3 years old. Males in particular can look dramatically different at age 3 compared to how they looked at 12 months.
This extended maturation period is normal for large breeds. It is also one reason proper nutrition during the first two years is so critical. Feeding a high-quality diet during this window supports healthy bone and joint development. Our guide on the best puppy food for American Bulldogs covers what to look for in a diet that supports steady growth.
Factors That Affect Size
- Genetics: The single biggest factor. The size of the parents -- and the bloodline behind them -- gives you the best prediction of adult size. This is where pedigree research becomes valuable.
- Type: As discussed above, Johnson types run heavier than Scott types. Hybrids fall in between.
- Sex: Males are consistently larger than females in both height and weight. The gap is typically 15 to 30 pounds at maturity.
- Nutrition: Puppies that are underfed or fed low-quality food may not reach their genetic potential. Overfeeding can also cause problems, leading to excess weight that stresses growing joints.
- Spay/Neuter Timing: Early spaying or neutering can affect growth plate closure, sometimes resulting in a slightly taller but less muscularly developed dog.
How to Tell if Your American Bulldog Is a Healthy Weight
Size and weight are not the same thing. A 100-pound American Bulldog can be perfectly fit or significantly overweight depending on body composition. Here is what to check:
- Rib check: You should be able to feel your dog's ribs without pressing hard. If you cannot feel them at all, your dog is likely carrying too much fat.
- Waist from above: Looking down at your dog from above, there should be a visible waist behind the ribcage. No waist means excess weight.
- Belly tuck: From the side, the belly should tuck up slightly behind the rib cage rather than hanging level or sagging.
- Energy and movement: A healthy-weight American Bulldog should move freely and have good stamina. If your dog tires quickly or seems stiff, weight may be a factor.
American Bulldogs are a naturally muscular, thick breed -- so do not compare them to leaner breeds. But they should still have definition and athletic shape. Understanding the breed's temperament and activity level helps you gauge whether your dog is getting enough exercise to stay in shape.
If you are buying an American Bulldog and size is important to you, ask the breeder about the parents' weights and look at the pedigree. Past generations tell you a lot about what to expect.
Frequently Asked Questions
How big do American Bulldogs get?
Males typically stand 22 to 28 inches tall and weigh 75 to 120 pounds. Females stand 20 to 25 inches and weigh 60 to 90 pounds. Final size depends on type, genetics, and nutrition.
At what age is an American Bulldog fully grown?
Most American Bulldogs reach their full height by 12 to 14 months. However, they continue to fill out and add muscle mass until they are 2 to 3 years old. Males especially can change a lot between year one and year three.
Are Johnson American Bulldogs bigger than Scott types?
Yes. Johnson (Bully) type American Bulldogs are generally stockier and heavier, weighing 90 to 120 pounds. Scott (Standard) types are leaner and more athletic, typically weighing 70 to 100 pounds. Hybrids of the two types fall somewhere in between.
How much should my American Bulldog weigh at 6 months?
At 6 months, male American Bulldogs typically weigh 45 to 65 pounds and females weigh 35 to 55 pounds. These are averages and individual dogs may vary based on type and genetics. If your pup is growing steadily and your vet is happy, you are on the right track.
How can I tell if my American Bulldog is overweight?
You should be able to feel your dog's ribs without pressing hard. When viewed from above, there should be a visible waist behind the ribs. From the side, the belly should tuck up slightly. If the ribs are buried under fat or there is no waist definition, your dog may be carrying too much weight. Talk to your vet about a healthy target weight for your specific dog.