Bernhardiner, St Bernhardshund, Alpine Mastiff, or simply the Saint Bernard – no matter which name you know them by – pretty much everyone is familiar with, or can recognize, this gentle breed. If you have decided that you would like to bring one of these sweet dogs home, you will likely have plenty of questions. One of the most common is just how big you can expect a Saint Bernard to get! I spent some time researching the breed standard and all aspects of their size. I’ve documented it all together here for your reference.

So, how big do Saint Bernards get? Saint Bernards are classified as a very large dog breed, typically ranging from 26-30 inches in height and weighing between 120-180 pounds. Males are generally larger than females, and you can expect them to gravitate towards to upper end of the height and weight range, with females being more likely to be towards the lower end.

Saint Bernards are one of the largest dog breeds in the world, but they are also one of the gentlest.

The traits they are most known for include their friendliness and ability to be outgoing, and their extremely high tolerance and patience with even the smallest of children.

Beyond this they have a rich history and a dog that are fondly remembered and thought about. A testament to their nature, power and strength is the way they have been historically used to rescue people lost in the Swiss Alps. They really are saints!

Although many still work today on rescue missions, due to a number of desirable traits and tendencies, it is common to see them kept as pets where they soon become beloved members of the family.

Let us now now explore the Saint Bernard size in further detail. We will be covering some their growth cycle, when you can expect one to reach their full adult size and the factors that influence how big they will ultimately get.

We will also take a look at when you can expect them to reach mental maturity and if this dog is right for you, in relation to their large size.

So, if you are serious about taking on this breed, then be sure to keep on reading to educate yourself on all that you will need to know.

Average Height, Weight And Size Of A Saint Bernard?

As one of the biggest breeds in the world, the size, weight, and height of a Saint Bernard can be summed up in just one word – huge!

So big that they surpass the large category and have been classified as ‘very large’. Not many breeds share the same category!

A standard size male Saint Bernard will weigh anywhere from 140 to 180 pounds. Their height at the shoulders is roughly 28 to 30 inches.

For a female Saint Bernard, they will weigh anywhere from 120 to 140 pounds. Their height at the shoulder should be roughly 26 to 28 inches.

Although these are only an average – your Saint Bernard could be smaller or much larger. It will depend entirely on the dog, along with a range of factors that influence their final size. We will be looking at these in a future section so keep reading!

Either way if you opt for this breed you will be taking on a big dog and because of this, training will need to be a priority.

Its important that you do so while they are still young; this way they are much more manageable and less likely to have developed a stubbornness and undesirable behaviors.

Thankfully, this is a very intelligent breed and they do tend to learn quickly.

They are also not an aggressive breed by nature, and will only become so as a last resort to protecting a close family member.

Training through positive reinforcement techniques works especially well, and keeping treats on hand will go a long way to ensuring their compliance.

Equally, early socialization is advised too. This means introducing them to a lot of different people, animals, sights, sounds and experiences as you can.

This is imperative to ensure that your St Bernard puppy grows up to be a respectable, well-behaved and all-rounded dog.

At What Age Is A Saint Bernard Fully Grown?

The average female Saint Bernard should reach their full height by around 15-18 months. Whereas a male will take slightly longer, continuing to grow until they are around the 18 to 24-month mark.

This is just for height, and weight is another matter altogether.

Either way, not all Saint Bernards will grow at the same rate. So, there is no definitive answer to this question.

You may find that there are some Saint Bernards who have reached their full adult size by their second birthday.

Then you may also see one, even from the same litter, who does not reach their full adult size until they are well into their 4^th year.

There is no real explanation as to why this occurs, but genetics obviously play a central role. Nevertheless, females usually do stop growing before their male counterparts.

To know if your dog is on track with their weight and size, use the information below as a reference to help you.

Growth Of A Female Saint Bernard

At 3 months of age, a female should weigh in the vicinity of 37.6 pounds and 48.4 pounds.
Their size almost doubles by the time they are 6 months old, and their weight should be somewhere between 69.3 pounds and 88 pounds.
Once their 1^st birthday rolls around, your female Saint Bernard should fall within the range of 101.9 pounds to 136.4 pounds.

Growth Of A Male Saint Bernard

At 3 months of age, a typical male should weigh in the vicinity of 48.4 pounds to 56.1 pounds.
Their size will also almost double by the time they reach 6 months old, and their weight should be somewhere between 88 pounds and 103 pounds.
Once they have finished out their first year, your male Saint Bernard should fall within the range of 136.4 pounds to 165.9 pounds.

There is a simple estimation formula that you can also use:

Females should weigh approximately 2 pounds for each centimeter of height up to the shoulders.
Males should weigh approximately 2.2 pounds for each centimeter of height up to the shoulders.

Keep in mind that these are only estimations so there is no need to become overly concerned if your pup doesn’t seem to fit the mold.

When Do Saint Bernards Mentally Mature?

It can take several years for a Saint Bernard to mature mentally, and there are 6 distinct stages that they will go through from birth to adulthood.

Let us now take a look at each one, and what you can except during each one:

Neonatal Stage

The neonatal stage is the stage between birth and when your puppy’s eyes open at approximately 10 days of age.

When they are in this stage, they are completely dependent on their mothers. During this stage, all your dog will do is eat, sleep, and poop.

Transitional Stage

The next stage is the transitional stage and it only lasts for about 7 days.

It starts when your dog has opened their eyes and is extremely important to their overall development.

As they begin to notice the world around them, they become curious about sights and sounds.

Socialization Stage

Next comes the socialization stage at around the age of 3 weeks.

This is a vital stage for your Saint Bernard’s mental maturity because they will learn how to properly interact with others – both human and animal.

During this period, you should be sure to introduce your pup to as many new situations, sounds, people, and places as possible.

This will help your pet feel comfortable in a variety of situations once they are older.

Juvenile Stage

From about the age of 3 months to 6 months, your Saint Bernard will be in what is called the juvenile stage.

Think of a curious toddler who is always getting into mischief – this is how your pup will be. Although they may look like a dog that is mostly grown-up, their minds still function as a puppy.

They have short attention spans so you will need plenty of patience once you start their training. Keep at it though.

Saint Bernards are very intelligent, and training can help to keep them mentally stimulated.

Adolescent Stage

The adolescent, or teenager, stage comes next. If you do not neuter your pet early on, their hormones will rage uncontrollably for the first 2 years of their life.

This means that you will have to put up with territory marking and mounting whatever they can get their paws on!

Adult Stage

You will finally be able to relax once they reach the adult stage. When exactly this will happen for your particular pup is difficult to say but it will become obvious by the way your Saint Bernard is now respectful, calm, and dignified.

This is your reward for all the patience you showed waiting for them to get to this stage.

Every dog is different, but the majority of Saint Bernards stay in the puppy stage for at least 3 to 4 years.

This in no way diminishes their intelligence but you may have to work a little harder at training.

Their playful antics will no doubt amuse you, but adult “puppies” seem to forget just how big they are. It is absolutely essential that you start training your pup as soon as you bring them home.

Along with basic commands, your new pet needs to be leash trained. If they are not taught to walk on a leash properly and they suddenly decide to take off in a different direction, you will definitely end up on the ground.

Saint Bernards are so big that it would be irresponsible to have one that you cannot control.

Factors That Influence The Size And Growth Rate Of A Saint Bernard?

There are several factors that influence the size and growth rate of a Saint Bernard.

The main factor that you will need to know about is the sex of the dog.

If you want a smaller Saint Bernard, choose a female pup. If you are happy to have an exuberant behemoth by your side and do not mind how big they grow, choose a male pup.

Whether or not your dog is purebred will also affect their size and growth rate.

For example, if one parent is a Saint Bernard and the other is a Lab, your dog will end up being much smaller than if both the parents were purebred Saint Bernards.

When it comes to their genetics, another important factor is the dogs in which they came from. Not only just the parental dogs, but the other dogs in the lineage. In fact, dogs can acquire genes from dogs as far back as 5 generations when it comes to size.

For this reason, you should look to discuss sizing with the breeder, as they will be able to give you some insight as to what to roughly expect from the litter and of litters past.

Another factor that could be affecting the growth of your pup is a parasite infection. Roundworms or hookworms that lodge in the intestines slow down a dog’s growth because they “steal” calories that your Saint Bernard needs for proper growth and development.

Of course, this is not something that every dog experiences, and if they were to, appropriate medication and treatment can stop these in their tracks. Just be sure to consult with your vet and ensure your dog has regular checkups to ensure that they are growing in accordance with expectations.

Finally, diet plays a large role in determining the size and growth rate of your pup.

You should always feed your dog a premium diet that is as natural as possible. To know how much you should be feeding your pup, follow the chart on the bag or speak with your vet.

Processed foods, inedible table scraps etc. do not do a dog any good. Foods with a lack of nutrition should not be fed, as they provide little nutrition and no benefit to a dog.

Excess food is as bad as undernourishment, so be sure that your dog does not overeat or exceed their daily energy requirements. Any excess weight gain beyond what they will need will simply place unnecessary pressure on joints, limbs and their frame in general.

Is The Size Of A Saint Bernard Right For You?

Saint Bernards are large dogs that have certain requirements to keep them happy and healthy. Not everyone can meet these needs and they may need to choose a smaller dog breed.

Because they are such big animals, Saint Bernards require room to move.

They are not well adapted to apartment living and they hate being left alone for long periods.

Although they do not need a ton of exercise, they do need a couple of good walks per day. Even better is a fenced yard where they can romp to their heart’s content.

Try to keep their activity level down when the weather is very warm because this breed does not handle heat well.

However, you will never see a happier Saint Bernard than when they are having a good romp in the snow with their humans!

Finally

Despite their huge size, Saint Bernards are a terrific dog breed with a wonderful temperament. They are often described as gentle, friendly and calm.

If you are serious about getting this dog, then you should be willing to do your research and due diligence ahead of time.

Going through a reputable breeder comes strongly recommended for a multitude of reasons. Primarily however, it will ensure that your dog has been brought into the world in an ethical and moral manner.

It also should mean that they have come from a superior lineage of dogs, and are more likely to meet the breeds standards for size, height and weight.

Besides, dogs bred in better practices will often be happier, healthier dogs.

If you did want to begin your research on breeders, then going through an organization such as the American Kernel Club (AKC) is one of the best places to start.

Want to learn more about the Saint Bernard breed? Check out my other guides below:

Related guides you may want to read:

How Big Do Dogs Get?

Jeremy Williams

I am an experienced pet owner with decades of experience owning a number of different pets, from traditional pets like dogs and cats, to the more exotic like reptiles and rodents. I currently own a Cockapoo (pictured) called Bailey. I am also the main writer and chief editor here at Pet Educate; a site dedicated to sharing evidence-based insights and guidance, based on my vast pet ownership knowledge, experience, and extensive research.

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