Neapolitan Mastiff Growth Chart – Size & Weight Chart

Neapolitan Mastiffs hail from Southern Italy and are known to be family guard dogs. If you are the owner of one of these dogs, then a Neapolitan Mastiff growth chart will help you.

They are fondly seen as gentle giants because of their affectionate nature and imposing appearance. Some people call them Mastinos or Neos.

Because of this breed’s massive size, you will need a lot of space to make them comfortable.

Apartment dwellings are not ideal unless you are able to take your dog outside a lot or if your apartment has enough space.

Neapolitan Mastiffs also require care and attention because they drool quite a lot. 

Neapolitan Mastiffs have thick facial wrinkles because of their loose skin. This unique breed has a slow and cautious gait, but this does not make last powerful.

Neos are wary of strangers, but they are not fighting dogs. However, they will ferociously protect their owners if the need arises.

When Is A Neapolitan Mastiff Fully Grown? 

Neapolitan Mastiff Fully Grown

This is not a simple question that can be answered on a whim. Because of the way different breeds develop it may not be a totally accurate answer especially because dogs have differences even when they are a part of the same breed.

This is why we should understand the breed standard and how they develop but also leave room for margin of error.

Neapolitan Mastiffs are known to grow exponentially and some of them even have a 50 to 150 lb weight increase during the first 15 months of their lives.

This would mean radical changes in their development and the need for their owner to understand what is happening in their biology.

As an owner, it will definitely affect you as it pertains to the space provisions given to this breed as well as accessories such as collars. 

Most Neapolitan Mastiffs are fully grown between the age of 15 to 18 months. In their first year of life, they will have more growth in height than width. 

Then after the one-year mark, their head bones and chest will see rapid growth.

Neapolitan Mastiff Weight Chart

The Neapolitan Mastiff weight chart below gives weight estimations of your Neacpolitan Mastiff. You should not be worried if you find that the figures stated are not the same as your actual dog weight. 

Also, there are a number of reasons why dogs develop differently such as their diet,  exercise schedule, and genealogy.

If you are dealing with a Neapolitan Mastiff that weighs considerably less than what appears in the charts then it is best that you conduct a physical assessment to ensure that he is in good health.

If you are unsure, then the best thing to do is check with your veterinarian who will give you proper advice on your dog health

To use the Neapolitan Mastiff growth chart, all you have to do is have a proper record of your dog’s age and match it to the closest age on the left column of the chart.

Then you can look for the weight range that goes along with this age.

Neapolitan Mastiff Puppy Weight Chart

AgeWeight (lbs)Weight (kg)
3 Months44 - 48.5 lbs20 - 22 kg
6 Months77 - 88 lbs35 - 40 kg
8 Months95 - 106 lbs43 - 48 kg
10 Months114 - 128 lbs52 - 58 kg
12 Months121 - 137 lbs55 - 62 kg
16 Months132 - 143 lbs60 - 65 kg
18 Months143 - 148 lbs65 - 67 kg

Neapolitan Mastiff Growth Chart – What To Expect

Neapolitan Mastiff Puppy Development

Birth – 2 Weeks

Neapolitan Mastiffs are quite active when they are young. But they tend to be couch potatoes when they get older.

Neos are born into litter sizes of about 4 -12 pups, and they are heavily dependent on their mothers who feed, cleanse and keep them warm.

Allow them to have this time with their mothers without human intervention.  

If for some reason one of the puppies is rejected by their mother, you can step in to help. Remember that they need to be kept warm, and they will need a canine milk replacement.

Neapolitan Mastiffs do not have eyesight or proper use of their limbs at this time.

3 Weeks – 12 Weeks 

You will notice many transitions in your Neapolitan Mastiff during this time. One of the major shifts that your puppy must go through is a change in his diet as he will now be ready to eat solid foods.

And this change in eating should be done gradually and carefully because your Neapolitan Mastiff is still very young.

If you are giving him a high-quality puppy chow, or food that you have prepared at home, it must be the correct size and texture for his soft and tender mouth.

Some kibble bits may be too hard for him, so you should have some form of liquid so that it will be easy for him.

At the end of this stage, females usually weigh around 17 to 20 kg, while males should weigh between 19 and 22 kg.

4 Months – 9 Months

During this stage, you can expect your Neapolitan Mastiff to enter their first heat cycle which happened between the ages of 6 to 9 months.

It usually lasts about 2 weeks, and you should be wary of your dog acting strangely because of his need to mate with other dogs.

Neapolitan Mastiff Development

He may run away to be with other dogs, so ensure that your yard is properly fenced. When your Neapolitan Mastiff is 6 months old, the females usually weigh between 31 and 36 kg while the males weigh around 35 to 40 kg.

10 Months – 18 Months

During this stage, your Neapolitan Mastiff will be almost done with growth, so they should be almost at the size they need to be.

They are considered full-grown when they are about 19 -22 months of age.

Your Neapolitan Mastiff is in need of socialization training especially because he is a giant breed and would be able to do more damage.

The males usually weigh around 4 to 62 kg while females should weigh between 46 and 55 kg. 


By this time your Neapolitan Mastiff would be full-grown. At this stage, Neapolitan Mastiff steps into a sedentary lifestyle, but you should make sure that he has enough exercise.

This does not mean that they do not enjoy playtime with their humans. You should also reduce the amount of food you give him.

Also, give him less protein because they require more protein in their younger years.

Neapolitan Mastiff Weight Chart

How Big Do Neapolitan Mastiffs Get? 

Because Neapolitan Mastiffs are giant breed dogs, owners want to know exactly how big they will get so that they can make proper accommodations for them.

Use the weight chart within this article for starters. There are other methods available aside from a weight chart.

Looking at your Neapolitan parents is the most accurate way of telling his future size.

Because of genetics that is passed down through generations, you can have a clear picture of your Neapolitan’s eventual size.

You can also examine his paws because dogs usually have more growing to do when their paws are bigger in proportion to the rest of their body. By the time they are fully grown, they grow into their paws and their heads.

A DNA test is also a viable option because it can map your Neapolitan’s genealogy to find out if there are any other breeds within his ancestry that may throw off calculations.

Some breeders sell dogs that are not the exact breed that they claim.

Will Neutering/Spaying My Neapolitan Mastiff Affect His Growth? 

It is best if your Neapolitan Mastiff waits until 19-22 months before spaying or neutering takes place.

This will give enough time to completely develop before this procedure because spaying and neutering can affect your dog’s development. Your Neo will have a better chance of living a normal life.

Many owners have difficulty monitoring the heat cycle of their dogs as well as the behavioral changes they may experience.

However, you need to understand spaying or neutering could have effects on their body both positive and negative.

Neapolitan Mastiff Puppy Growth Chart

Neutering can affect your dog joints because the hormones in your dog’s body may be disrupted during their development.

This does not mean that there aren’t good reasons to have your dog spayed or neutered.

It can prevent unwanted pregnancy, and it can even reduce the likelihood of your dog developing certain cancers. Some owners notice that their dog’s aggression is reduced after spaying and neutering.

Neapolitan Mastiff Height Chart 

Neapolitan Mastiffs are giant dogs, therefore you can expect that they will end up with a height measurement that measures more than many other breeds.

It is quite easy to take any dog’s height measurement. Simply place the dog against a flat surface like a wall and take note of the point of his withers. His withers is the highest point on his shoulder blade.

Make sure about your dog is standing up straight and not looking sideways. After you record, this measurement use a carpenter’s level and extent that point to the end of the wall.

Then all you need to do is use a measuring tape to measure the point in a straight line to the floor. This measurement is your dog’s height.

English Mastiff vs Neapolitan Mastiff Size

Both the Neapolitan Mastiff and the English Mastiff are similar in appearance. Not only that, but they both weigh over 100 lb in adulthood which makes them Giants dog breeds.

Both of these dogs have that characteristic Mastiff appearance with which is a sturdy build and a large head. 

On average, English Mastiffs are larger than Neapolitan Mastiff. English Mastiffs can weigh around 120 to 230 lb while Neapolitan Mastiffs usually weigh approximately 110 to 150 lb.

Both of these dog breeds can weigh more or less than the ranges that we have mentioned. You will require a lot of space for both of these dogs.

They are double-coated with short dense fur. The English Mastiff has three coats colors which are brindle fawn and apricot.

But most of them have dark-colored muzzles. On the other hand, Neapolitan Mastiffs usually come in blue, black, mahogany and, tawny, with or without spots of brindle. 

Factors That Affect Neapolitan Mastiff Growth 

Neapolitan Mastiff Nutrition

Genetics & Gender

Genetics usually play a major role in the life of a Neapolitan Mastiff because they inherit their large size from their ancestors.

You will find that a Neapolitan is the average size of his parents.

Gender plays a role as well because males are larger than females and because they have different hormones in their bodies, the sexes tend to develop at different rates as well. Females usually attain adulthood before males do.


Your Neapolitan Mastiff should be fed high-quality dog food. You can find a good type of kibble by checking the ingredients and making sure that animal protein is listed as the first ingredient.

This can be beef, chicken, turkey, salmon, and many more options. Also, make sure that they use whole ingredients that are good for his digestive system.

Make sure that there are no fillers that do more harm than good. Good dog food does not have grain, corn, or soy. It also will not have any artificial ingredients or harmful additives.

Physical Activity & Health

As a dog owner, it is important that you understand the physical limitations of your Neapolitan Mastiff.

This breed should conduct exercise in a controlled way so that joints and bones are not stressed out too much, especially while they are still in development.

Therefore, you should engage your Neapolitan mastiff in exercise for only short periods.

Short walks are perfectly fine but Neos do not make good jogging partners because they may hurt themselves. However, keep in mind that exercise is really essential to maintaining their weight.

What If My Neapolitan Mastiff Is Not The Right Weight

Some dog owners may be unsure about man Neapolitan Mastiff’s weight. This is not surprising because they are a giant breed.

There is a simple test that you can conduct while examining your dog to give you an idea about their weights.

Do a simple eye test or a hands-on test to determine if your Neapolitan Mastiff is overweight or underweight.

For the eye test, you can look down at your dog from an aerial view. If you can see his waist clearly when you know that he may be underweight.

His waist should not be sunken, to the point where you can distinguish a clear outline.

For the hands-on test, you need to place your hands on your Neapolitan back and run your thumb along his spine while spreading out your fingers. You should be able to feel the spine without pressing down too hard. 

Do the same thing while running your hands along his ribs. If you find that you are unable to feel his ribs but only fat then you know that is overweight. 

The best thing that you can do is visit your veterinarian who will give you a clear answer about your dog’s state of health.

Neapolitan Mastiff Genetics And Common Health Problems 

Neapolitan Mastiffs are prone to a number of ailments such as arthritis, bloat, and hip dysplasia. Joint health is also a major problem Neapolitan deals with because of its enormous size.

Remember that their skeletal system must carry the weight of their large muscles and extra skin. This is why you should ensure that their elbows and hips are evaluated on a continuous basis.

Bloat is also a serious concern, so it is better not to free-feed them with food or water because they may be tempted to eat or drink too quickly or in large amounts which causes gas.

This is serious because it sometimes leads to a ruptured stomach as well as other organ damage. Their portions should be kept small.

Final Words

If you are someone who is overly concerned about keeping a  perfectly neat house then a Neapolitan Mastiff may not be the dog for you.

They tend to drool all over the floor after they drink or eat. They also do this when they are nervous.

You will need to clean up after them constantly. However, they do not bark a lot so if you want a quiet dog they will suit you fine.

Remember that training is very important especially in their early years so that they can learn acceptable behaviors and not destroy your entire home.

Also, because of their loose skin, they need to be groomed properly especially in their skin folds which may develop bacteria if left moist.

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