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When Do Mastiffs Stop Growing? A Guide to Understanding Mastiff Growth Patterns

When Do Mastiffs Stop Growing

English Mastiffs are known for their massive size and impressive stature. They are one of the most giant dog breeds, weighing up to 230 pounds for males and 170 pounds for females. 

Their growth rate is astonishing, and they can take up to four or five years to reach their full size. Keeping track of their growth milestones is essential to ensure they are thriving.

A frequently asked question about English Mastiffs pertains to when their growth ceases. Compared to other breeds, Mastiffs have a more gradual growth rate, which elements like genetics, nutrition, and physical activity can influence.

On average, Mastiffs stop growing around two or three years of age, but some may continue to grow until they are five. It’s crucial to monitor their growth and ensure they are growing slowly and slowly, as this can lead to health problems.

Monitoring the development of your Mastiff is crucial for their well-being. Regularly recording their weight and height and comparing these measurements to the breed’s standards can provide insights into their health. 

Puppy Growth Timeline

Developing a Mastiff puppy is a steady journey that requires time, patience, and regular training.

The puppy depends entirely on its mother for sustenance for two weeks. This period is vital for the puppy as it starts to hone its senses and motor abilities.

Around one month of age, the puppy begins to socialize with its littermates and is introduced to wet food. This is an essential time for the puppy to learn social skills and develop a healthy relationship with food.

At two months, the puppy is separated from its mother and begins obedience training. This is when the puppy will learn basic commands and start to bond with its owner.

From three to ten months of age, the puppy will experience monthly growth milestones. It is crucial during this time to continue training and socialization to establish good behavior and prevent any bad habits from forming.

When the puppy is one year old, it is time to celebrate its first birthday! The puppy will continue to grow and develop but at a slower rate.

It is essential to continue training and socialization throughout the dog’s life to ensure a well-behaved and happy Mastiff.

What Happens After a Year?

Mastiffs are known for their unique growth pattern, characterized by rapid growth during the first year of life. When a Mastiff reaches one year old, it will have grown substantially. 

However, despite this impressive growth rate, Mastiffs are not fully grown at one year old.

Mastiffs typically grow until they reach about five years of age. While their growth rate slows after their first year, they continue gaining weight and size. 

During this growth phase, keeping an eye on a Mastiff’s development is crucial to ensure they’re growing healthily and not becoming overweight. 

Proper nutrition and exercise are vital for Mastiffs as they grow. Feeding them too much or too little can result in health issues like joint problems and obesity. 

Collaborating with a veterinarian to create a personalized nutrition and exercise regimen for your Mastiff is essential.

Full-Grown English Mastiff

There are general size guidelines for a fully grown English Mastiff. The American Kennel Club (AKC) suggests that male Mastiffs should be at least 30 inches tall at the shoulder, whereas females should measure at least 27.5 inches. However, these figures are merely guidelines and individual Mastiffs might vary.

Weight is another crucial aspect when determining the size of a mature Mastiff. Males usually weigh between 160 and 230 pounds, while females range from 120 to 170. 

It’s essential to remember that these are average figures, and some Mastiffs might be below or above these typical ranges.

It’s also worth noting that the AKC has specific standards for Mastiff height. According to these standards, a male Mastiff should be between 30 and 36 inches tall at the shoulder, while a female should be between 27.5 and 32 inches tall. 

However, it’s important to remember that these are just guidelines, and individual Mastiffs may fall outside these ranges.

Factors Affecting Mastiff Growth

Various factors influence the growth of Mastiffs. By comprehending these elements, owners can ensure optimal care for their dogs. Here are the key determinants that impact the growth of Mastiffs:


The genetics of Mastiffs greatly influence their growth. Their size and weight predominantly stem from the genes passed down from their parents. Hence, selecting a trustworthy breeder who offers insights into the puppy’s lineage is crucial.


Optimal nutrition is essential for the growth of Mastiffs. Ensuring a balanced and nutritious diet is critical to their development. When they’re puppies, a diet rich in protein and fat is vital due to their swift growth. Modifying their diet to cater to their evolving nutritional requirements is essential as they age.

Growth Spurts & Plateaus

Mastiffs go through several growth spurts and plateaus during their development. These periods of rapid growth are unpredictable and can vary from one dog to another. Owners should be aware of these growth patterns and adjust their care accordingly.

Neutering & Spaying

Altering a Mastiff through spaying or neutering can affect their growth and the health of their joints.

Evidence suggests that spayed or neutered Mastiffs might grow bigger and weigh more than those not altered. Mastiff owners must discuss the benefits and drawbacks of such procedures with their vet.

Physical Health

To ensure the robust development of a Mastiff, owners must emphasize routine health check-ups and uphold their pet’s physical health.

Consistent vaccinations and health evaluations are crucial to prevent diseases and injuries. Moreover, avoiding overexertion is essential, which can result in joint problems and other health concerns.

Frequently Asked Questions

Mastiffs are a sizable dog breed that often experiences swift growth in their initial year. Consequently, numerous owners are curious about their growth trajectory. Below are some common inquiries regarding the growth cessation of Mastiffs and related subjects:

When will my English Mastiff stop growing?

Mastiffs typically reach their full size and weight between 18 and 24 months of age. However, some may continue to grow until they are three years old.

It’s important to note that while growth may slow after the first year, Mastiffs can still gain weight and muscle mass as they mature.

How fast can my Mastiff grow?

During their initial year, Mastiffs can experience rapid growth, potentially gaining as much as 5 pounds every week. Monitoring their progress and providing proper nutrition is crucial for their healthy development.

Will my puppy experience growing pains?

Like humans, puppies can experience growing pains as their bones and muscles develop.

Mastiffs are prone to joint issues, so monitoring their growth and ensuring they are not overexerting themselves is essential. If you notice your puppy limping or showing discomfort, consult your veterinarian.

Common conditions in Mastiffs

Mastiffs are susceptible to specific health issues, including hip dysplasia, bloat, and arthritis. Regularly check your Mastiff’s well-being and consult a veterinarian if you observe any symptoms of distress or sickness.

Addressing weight concerns

Mastiffs are big dogs that need a lot of food. But make sure they don’t get too heavy. If they do, they can get sick. Talk to your vet about the best food and exercise for them.