When Is My Bull Terrier Full Grown?

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I have a lot of fun with my Bull Terrier puppy. He’s just a pure ball of energy when we play. However, I’m wondering how long is he going to stay as a puppy. Eventually, he will grow bigger. When is my Bull Terrier full grown?

When Is My Bull Terrier Full Grown?

A Bull Terrier reaches its full size at the age of 20 to 24 months. It achieves its full height as early as 12 to 14 months. A male Bull Terrier grows bigger than its female counterpart, but no study shows that it grows bigger first than the females.

Bull Terrier Development Stage

Watching your Bull Terrier grow is an exciting experience. From a cute little puppy to a full-grown adult, it exhibits major behavioral change. In the next section, we will discuss the different growth stages before a Bull Terrier reaches its full-grown size.

Bull Terrier sleeping on a pink stuffed toy

Neonatal Stage

A Bull Terrier’s neonatal stage starts from the day it was born until two weeks. Approximately, a two-week-old Bull Terrier weighs two to six pounds. During this stage, all its senses haven’t opened yet except its sense of smell.

A baby Bull Terrier would still have its eyes and ears closed. It’s usually unresponsive to human stimuli due to the lack of senses. 

However, a Bull Terrier puppy can only use its front legs to move and relies on its powerful sense of smell to locate its mother. Puppies are approximately 10,000 to 100,000 more sensitive than humans when it comes to their sense of smell. 

Transitional Stage

The transitional stage happens between two to four weeks. The Bull Terrier will weigh six to 15 pounds. At this stage, a Bull Terrier puppy opens its eyes and ears. However, the sense of sight comes first before your puppy can hear.

The puppy’s eyes open right after two weeks, and the longest takes three weeks. If you notice that your puppy doesn’t open its eyes within the mentioned range, consult the vet as your puppy might be experiencing developmental problems.

At the start of the three-week mark, your Bull Terrier puppy should be able to respond to sound. The puppy’s ears open up within this period. Their hearing is far more superior than ours.

A puppy can hear four times better and with a wider range of sound frequencies. It’s also during this stage that they start to grow their teeth. 

Socialization Stage

At around four to 12 weeks, it will weigh 15 pounds to 50 pounds. A Bull Terrier will start to socialize with its littermates by playing. It begins learning how to interact that will shape its future.

This stage will also help build its personality when it turns adult. Slowly and gently expose your Bull Terrier puppy to various situations, places and people. It will help develop a calmer temperament when your dog encounters different situations and people. 

Bull Terrier

Socialization is very important. Failure of doing so will cause behavioral problems in the future. Make sure to introduce new things with the right amount of praise and treats. Do it positively.

Ranking Stage

As your Bull Terrier turns three to six months has a size of 24 to 70 pounds. It will either dominate you or be submissive. It’s important to teach your puppy that you’re the dominant one. Dogs act on a hierarchical social structure. If they think they’re the alpha, they don’t follow rules. 

As the owner, you need to assert yourself as the alpha leader. Bull Terriers that have strong alpha owners do well in obedience training. It helps prevent aggressive and destructive behavior. While teaching your dog that you’re the alpha leader, do it while having fun. Don’t force affection from your dog. 

Always use positive reinforcement and avoid punishment.

Adolescence Stage

When your Bull Terrier reaches the age between six to 18 months, the adolescence stage starts. This stage is where your Bull Terrier reaches its full height that’s between 21 to 22 inches. It’s the stage where your dog starts to exhibit sexual behavior.

You can decide to neuter your dog within this stage. Your dog will also go through another teething stage and lose its puppy teeth. 

Related Questions

How Big Will My Bull Terrier Get?

On average, a Bull Terrier grows up to 50 to 70 pounds in weight and 21 to 22 pounds in height. Usually, the female weighs 45 to 55 pounds while the male Bull Terrier weighs between 55 to 70 pounds. 

What Age Does A Bull Terrier Mentally Mature?

Bull Terriers have a wide range of mental maturity. It could range between one to fours years of age. On average, however, they mature when they turn two years of age.


In summary, your Bull Terrier reaches its full size when it turns 20 to 24 months. While your dog is still young, it’s fun to observe the development he exhibits as he grows in size. It’s important to be knowledgeable in these stages to assist your Bull Terrier in attaining its full size.