How Much Should Mastiff Weigh? Mastiff Weight Calculator.

Updated on Jan 29, 2023

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Mastiff Growth

Did you just get the Mastiff puppy? And do you want to know when your Mastiff will stop growing and how big your Mastiff will get? Or do you want to know if your Mastiff is of the ideal weight for its age?

In this article, we will answer all these relevant questions related to Mastiff growth and weight.

If you do not own the Mastiff yet, make sure you purchase your Mastiff from an reputable Mastiff breeder. Also, check out our Mastiff buying guide and Mastiff price guide here.

You can also work with a reputable rescue to adopt a puppy.

It is important for you as a caring Mastiff owner to know if your Mastiff is growing normally and that your Mastiff is not overweight or underweight.

Extensive research studies have shown that most dogs are overweight because their owners spoil them with food, treats, and easy life styles. Most dogs eat way too much and do not get enough exercise. Research has also shown that one of the reasons many dogs die young is because they are overweight. However, you can extend your dog`s life by making sure your dog is of healthy weight and growth.

One final reason to keep track of your Mastiff`s weight and growth is that your Mastiff`s weight and growth pattern can tell you if your Mastiff has some underlying health conditions (such as bone, heart, hormone diseases). This is what recent research has shown.

This article contains the Mastiff growth calculator that you can use to predict your Mastiff`s adult weight. This article also contains the Mastiff growth chart and weight calculator that you can use to approximately tell if your Mastiff`s weight is in the normal range.

However, the more accurate method to predict and track normal growth in your Mastiff is by regularly weighing your Mastiff and recording the weight of your Mastiff with our free dog weight tracker and weight predictor. Our tool will tell you, first, a more accurate future weight of your Mastiff and, second, if your Mastiff is growing normally.

We designed our dog weight tracker and weight predictor based on a recent research study carried out by researchers from Banfield Pet Hospitals and the University of Liverpool. This study collected and analyzed the weight of over 6 million healthy dogs in the United States. The dogs studied included dogs in the Mastiff weight category.

Also, check out our Mastiff food calculator here to know how much food to feed your Mastiff based on your Mastiff`s weight and age.

Mastiff Weight and Growth Chart

Below is the typical growth chart and weight chart of Mastiffs at different stages in their lives.

Note that your Mastiff may be slightly heavier or lighter than what the chart says. The weight chart is an average weight chart.

Also, this growth chart is the combined growth chart of the male and female Mastiff.

To know how much food to feed your Mastiff at different ages and weights, check out our Mastiff feeding guide and calculator.

To know how much water your Mastiff needs to drink at different ages and weights, check out our Mastiff water drinking guide and calculator.

Note that the growth pattern of a female Mastiff can be slightly different from the growth pattern of a male Mastiff

. Therefore, later on in this article, we will provide you with the gender-specific growth chart for the male and for the female Mastiff.

Age	Average Weight	Typical Weight Range
15 Weeks	66 LBS	50 LBS – 83 LBS
20 Weeks	85 LBS	65 LBS – 106 LBS
25 Weeks	102 LBS	77 LBS – 127 LBS
30 Weeks	117 LBS	88 LBS – 146 LBS
35 Weeks	129 LBS	96 LBS – 163 LBS
40 Weeks	140 LBS	103 LBS – 177 LBS
45 Weeks	148 LBS	108 LBS – 189 LBS
60 Weeks	164 LBS	117 LBS – 210 LBS

When do Mastiffs Stop Growing and How Big Do They Get?

Your Mastiff will grow very fast in its first 55 weeks. At 55 weeks, your Mastiff will have reached 95 percent of its adult weight. Then your Mastiff will slowly stop adding more weight. At around 69 weeks (~16 months), your Mastiff should be at its maximum weight. Mastiffs stop growing at 69 weeks (~16 months).

The above discussion is general, and it applies to both male and female Mastiffs. However, male dogs usually grow at a different rate compared to female dogs

A male Mastiff will grow very fast in its first 55 weeks. At 55 weeks, a male Mastiff will have reached 95 percent of its adult weight at 55 weeks. A male Mastiff will then slowly stop adding more weight. At around 69 weeks (~16 months), a male Mastiff should have reached its maximum weight. Male Mastiffs stop growing at 69 weeks (~16 months).

Similarly, a female Mastiff will grow very fast in its first 54 weeks. At 54 weeks, a female Mastiff will have reached 95 percent of its adult weight at 54 weeks. A female Mastiff will then slowly stop adding more weight. At around 67 weeks (~16 months), a female Mastiff should have reached its maximum weight. Female Mastiffs stop growing at 67 weeks (~16 months).

See the growth graph of a Mastiff below.

As you can see in the Mastiff growth curve below, the Mastiff grows really fast in its early weeks, and then its growth levels off till it reaches 100 percent of the adult weight.

Mastiff Growth Calculator

Use the calculator below to estimate how big your Mastiff will get based on its current weight.

This Mastiff growth calculator is based on the typical weight curve of a Mastiff shown above. The calculator assumes that your Mastiff is growing normally, and not on its way to become overweight or underweight.

How Much Should a Mastiff Weigh?

Weight of the Mastiff. Weight in the dark green region is typical, though weight in the light green region is also possible

Adult Mastiffs typically weigh between 130 to 220 pounds.

Above is a graph that shows how much a Mastiff should weigh at different ages. Check where the weight of your Mastiff falls in the graph for its age.

It is totally fine if the weight of your Mastiff falls in either the dark green or light green region of the graph. However, weight in the dark green region is more typical for Mastiffs.

If the weight of your Mastiff falls outside both the dark and light green region for its age, then you should consult a vet.

Also, you can use the Mastiff weight calculator below to find the typical weight and the normal weight range of Mastiffs, male or female, of any age between 12 weeks and 100 weeks.

If you want to see how the weight of your Mastiff compares to that of other Mastiff`s of its age, enter the weight of your Mastiff in the calculator, and the calculator will show you where your Mastiff stands on the weight chart.

The calculator will also tell you if your Mastiff is within the normal weight range for the Mastiff.

This Mastiff weight calculator uses information from belpatt.fr and data from a research study on dog weight carried out by researchers at the University of Liverpool.

Please, talk to your vet before taking any decision on your pet`s weight and health.

What is the Height of the Mastiff?

The adult Mastiff is 27 to 32 inches tall at the shoulder. This is the average adult height of the Mastiff.

Is Your Mastiff Growing Normally? This is How to Tell

Puppy growth predictors, growth charts, and growth calculators like the ones above are approximate methods for predicting growth in dogs. However, these tools have limited capabilities. This is because each dog is unique and a dog`s growth may be different from that of the overall dog population.

A more accurate and scientific way to predict a dog`s growth is to measure the dog`s weight every week and record the weight. Doing this with your Mastiff will give you a clearer picture of how your Mastiff is growing.

You can use our free tool to track your Mastiff`s growth and weight over time. Our tool will also let you know if your Mastiff is growing normally.

Tracking your Mastiff`s weight will let you see the unique growth trajectory of your Mastiff. You can use this growth trajectory to accurately predict how big your Mastiff will get. The growth trajectory will also let you know very early if your Mastiff will become overweight or underweight.

Monitoring your dog`s weight is important because pet obesity is one of the leading causes of premature death in dogs. And these days, pets gain weight very easily because their owners spoil them with lots of treats and food. Catching early abnormal weight in your dog and correcting it (through diet changes, exercise) can significantly extend your dog`s life.

Below is what a normal growth pattern and what abnormal growth patterns look like in Mastiffs. You can compare your Mastiff growth trajectory against these references to see if your Mastiff is growing normally or you can use our automatic tool.

Tracking your Mastiff`s growth will let you catch abnormal growth

Click here to start using this free and useful Mastiff weight tracking tool to track healthy growth in your Mastiff.

How to Measure the Weight of your Mastiff

There are two methods you can use to measure your Mastiff`s weight.

The first method, which is the better and more accurate method to weigh your Mastiff, is to use a dog weighing scale.

Using a dog scale is important if you would like to monitor your Mastiff`s growth regularly to catch any abnormal growth early.

Having a scale for weighing your Mastiff will make it easy for you to weigh your Mastiff regularly without any trouble.

The scale that we recommend for weighing the Mastiff is this high durability and affordable W.C Redmon Precision Digital Pet Scale. Click here to check out this scale on Amazon.

Pet Scale for Accurately Weighing Your Mastiff

The second method is to use a bathroom scale to weigh yourself while holding your Mastiff. Then use the same scale to weigh yourself without your Mastiff. Then calculate your weight when holding your dog minus your weight when not holding your Mastiff. This method is illustrated in the picture below.

However, note that this method of holding your dog on a scale is not very accurate, and it may be difficult for you to use this method to weigh your Mastiff if your Mastiff is very heavy or if your Mastiff is the type that would not stay still while being held.

How to measure the weight of your Mastiff

How Fast Do Mastiffs Grow? Mastiff Growth Rate

Starting from 3 months of age, Mastiffs grow at a rate of 4.02 pounds per week (1.82 Kilograms per week) on average. Starting at 4 months, your Mastiff will gain 3.69 pounds (1.67 Kilograms) every week on average.

At 5 months of age, your Mastiff will grow at a rate of 3.35 pounds per week (1.52 Kilograms per week) on average. Then at 6 months, your Mastiff will gain 3.02 pounds (1.37 Kilograms) every week on average.

See the growth rate chart of the Mastiff below

Age (Months)	Growth per week (Pounds)	Growth per week (Kg)
3 Months	4.02	1.82
4 Months	3.69	1.67
5 Months	3.35	1.52
6 Months	3.02	1.37
7 Months	2.68	1.22
8 Months	2.35	1.07

Size of Male Mastiff Versus Size of Female Mastiff

The average size of a male Mastiff is 190 pounds (86 kg) while the average size of a female Mastiff is 143 pounds (65 kg).

In general, male dogs are usually bigger than female dogs.

Size of Male Mastiff versus Size of Female Mastiff

Male Mastiff Weight and Growth Chart

The growth pattern of Male dogs is also different from that of Female dogs.

Adult male dogs are generally bigger in size than adult female dogs.

Below is the typical growth and weight chart of a Male Mastiff.

Age	Average Weight	Typical Weight Range
15 Weeks	73 LBS	63 LBS – 83 LBS
20 Weeks	94 LBS	82 LBS – 106 LBS
25 Weeks	113 LBS	98 LBS – 127 LBS
30 Weeks	129 LBS	112 LBS – 146 LBS
35 Weeks	143 LBS	123 LBS – 163 LBS
40 Weeks	155 LBS	133 LBS – 177 LBS
45 Weeks	165 LBS	141 LBS – 189 LBS
60 Weeks	183 LBS	155 LBS – 210 LBS

Female Mastiff Weight and Growth Chart

The growth pattern of female dogs is different from that of male dogs. On average, female dogs grow faster than males and reach full size earlier. For this reason, it`s important that the standard height and weight charts for dogs are gender-specific.

Also, adult female dogs are generally smaller in size than adult male dogs.

Below is the typical growth and weight chart of a Female Mastiff.

Age	Average Weight	Typical Weight Range
15 Weeks	57 LBS	50 LBS – 64 LBS
20 Weeks	73 LBS	65 LBS – 82 LBS
25 Weeks	88 LBS	77 LBS – 98 LBS
30 Weeks	100 LBS	88 LBS – 113 LBS
35 Weeks	111 LBS	96 LBS – 125 LBS
40 Weeks	120 LBS	103 LBS – 136 LBS
45 Weeks	127 LBS	108 LBS – 145 LBS
60 Weeks	139 LBS	117 LBS – 161 LBS

Mastiff Growth Stages

Your Mastiff will go through a number of developmental stages on its journey to adulthood. Your Mastiff`s growth pattern can be categorized into 6 distinct stages: Neonatal, Transitional, Socialization Period, Juvenile Period, Adolescent Period, and Maturity.

You can know the developmental stage of your Mastiff based on how old your Mastiff is.

1. Mastiff Neonatal Period

Mastiff Neonatal Period is from Birth to 2 weeks. During this stage, the Mastiff puppy will be totally dependent on its mother. The Mastiff puppy`s eyes will still be unopened with no sense of vision. The Mastiff puppy will only have the senses of taste and touch

2. Mastiff Transitional Period

Mastiff Transitional Period is from 2 weeks to 3 weeks. During this stage, the Mastiff puppy will continue to develop a better sense of hearing and taste. The puppy`s teeth will start coming through and its eyes will begin to open.

During this stage, the Mastiff puppy begins to crawl forward and backward, begins to stand, begins to wag its tail. This is also the age where your puppy’s personality begins to develop.

3. Mastiff Socialization Period

Mastiff Socialization Period is from 3 weeks to 14 weeks. During this stage, the Mastiff puppy will be able to fully use all of its senses (vision, smell, touch, hearing, taste), and the puppy will learn to survive without its mother.

Also during this stage, the Mastiff puppy learns how to act like a dog (biting, chasing, barking, etc). The rapid learning and socialization of the puppy occur at this stage, and what the Mastiff puppy learns in this stage will have a long-term effect on the puppy`s behavior as an adult.

4. Mastiff Juvenile Period

Mastiff Juvenile Period is from 3-4 Months to 5-14 months. During this stage, the Mastiff puppies will attempt to clarify and resolve their boundaries. Their baby teeth start getting replaced by adult teeth.

5. Mastiff Adolescent Period

Mastiff Adolescent Period is from 5-14 Months to 2-3 Years. Mastiffs go through social and sexual maturity during this stage.

6. Mastiff Maturity Period

Mastiff Maturity Period is from 1 year to 4 years. At this age, your Mastiff will transition to full adulthood.

Male Mastiff Weight/Growth Chart in KG

The growth pattern of Male dogs is also different from that of Female dogs.

Adult male dogs are generally bigger in size than adult female dogs.

Below is typical growth and weight chart of a Male Mastiff in Kilograms (kg).

Age	Average Weight	Typical Weight Range
15 Weeks	33 KG	28 KG – 37 KG
20 Weeks	42 KG	37 KG – 48 KG
25 Weeks	51 KG	44 KG – 57 KG
30 Weeks	58 KG	50 KG – 66 KG
35 Weeks	65 KG	56 KG – 74 KG
40 Weeks	70 KG	60 KG – 80 KG
45 Weeks	74 KG	64 KG – 85 KG
60 Weeks	83 KG	70 KG – 95 KG

Female Mastiff Weight/Growth Chart in KG

Also, adult female dogs are generally smaller in size than adult male dogs.

Below is typical growth and weight chart of a Female Mastiff in Kilograms (kg).

Age	Average Weight	Typical Weight Range
15 Weeks	25 KG	22 KG – 29 KG
20 Weeks	33 KG	29 KG – 37 KG
25 Weeks	39 KG	35 KG – 44 KG
30 Weeks	45 KG	40 KG – 51 KG
35 Weeks	50 KG	43 KG – 57 KG
40 Weeks	54 KG	46 KG – 62 KG
45 Weeks	57 KG	49 KG – 66 KG
60 Weeks	63 KG	53 KG – 73 KG

How Much Should a 12-Week-old Mastiff Weigh?

The average weight of a 12-week-old female Mastiff is 46.3 lbs (21.0 kg).

The typical weight range of a 12-week-old female Mastiff is from 39.9 lbs to 52.6 lbs (18.1 kg to 23.8 kg).

The average weight of a 12-week-old male Mastiff is 60.2 lbs (27.3 kg).

The typical weight range of a 12-week-old male Mastiff is from 51.5 lbs to 68.9 lbs (23.4 kg to 31.3 kg).

However, a recent research study on dog weight shows that 12-week-old female Mastiffs can normally weigh as low as 39.9 lbs (18.1 kg) and as high as 52.6 lbs (23.8 kg)

Correspondingly, 12-week-old male Mastiffs can normally weigh as low as 51.5 lbs (23.4 kg) and as high as 68.9 lbs (31.3 kg)

How Much a 12-week-old Female Mastiff Should Weigh

How Much a 12-week-old Male Mastiff Should Weigh

How Much Should a 4-Month-old Mastiff Weigh?

The average weight of a 4-month-old female Mastiff is 60.6 lbs (27.5 kg).

The typical weight range of a 4-month-old female Mastiff is from 53.5 lbs to 67.8 lbs (24.3 kg to 30.7 kg).

The average weight of a 4-month-old male Mastiff is 78.0 lbs (35.4 kg).

The typical weight range of a 4-month-old male Mastiff is from 67.8 lbs to 88.3 lbs (30.7 kg to 40.0 kg).

However, a recent research study on dog weight shows that 4-month-old female Mastiffs can normally weigh as low as 53.5 lbs (24.3 kg) and as high as 67.8 lbs (30.7 kg)

Correspondingly, 4-month-old male Mastiffs can normally weigh as low as 67.8 lbs (30.7 kg) and as high as 88.3 lbs (40.0 kg)

How Much a 4-month-old Female Mastiff Should Weigh

How Much a 4-month-old Male Mastiff Should Weigh

How Much Should a 6-Month-old Mastiff Weigh?

The average weight of a 6-month-old female Mastiff is 85.4 lbs (38.8 kg).

The typical weight range of a 6-month-old female Mastiff is from 75.6 lbs to 95.3 lbs (34.3 kg to 43.2 kg).

The average weight of a 6-month-old male Mastiff is 109.5 lbs (49.7 kg).

The typical weight range of a 6-month-old male Mastiff is from 95.5 lbs to 123.6 lbs (43.3 kg to 56.1 kg).

However, a recent research study on dog weight shows that 6-month-old female Mastiffs can normally weigh as low as 75.6 lbs (34.3 kg) and as high as 95.3 lbs (43.2 kg)

Correspondingly, 6-month-old male Mastiffs can normally weigh as low as 95.5 lbs (43.3 kg) and as high as 123.6 lbs (56.1 kg)

How Much a 6-month-old Female Mastiff Should Weigh

How Much a 6-month-old Male Mastiff Should Weigh

How Much Should a 1-Year-old Mastiff Weigh?

The average weight of a 1-year-old female Mastiff is 134.6 lbs (61.0 kg).

The typical weight range of a 1-year-old female Mastiff is from 114.0 lbs to 155.1 lbs (51.7 kg to 70.4 kg).

The average weight of a 1-year-old male Mastiff is 175.6 lbs (79.6 kg).

The typical weight range of a 1-year-old male Mastiff is from 149.5 lbs to 201.6 lbs (67.8 kg to 91.4 kg).

However, a recent research study on dog weight shows that 1-year-old female Mastiffs can normally weigh as low as 114.0 lbs (51.7 kg) and as high as 155.1 lbs (70.4 kg)

Correspondingly, 1-year-old male Mastiffs can normally weigh as low as 149.5 lbs (67.8 kg) and as high as 201.6 lbs (91.4 kg)

How Much a 1-year-old Female Mastiff Should Weigh

How Much a 1-year-old Male Mastiff Should Weigh

How to Tell If Your Mastiff is Overweight

As mentioned earlier in this article, a very accurate way to know if your Mastiff puppy is on its way to becoming overweight is by weighing your dog every week and recording its weight. This will show you the growth trajectory of your Mastiff puppy. And a close look at your puppy`s growth trajectory will tell you if your Mastiff puppy will be overweight or underweight. This method is relatively easy to use.

You can use our free online tool to track your Mastiff puppy`s growth curve.

However, if you do not have a record of the weekly weights of your Mastiff, and you want to tell if your dog is overweight, underweight, or of normal weight, then you can use a chart called the body condition chart shown below. This method requires some expertise to use, and it is further discussed below.

Overweight, Underweight and Ideal Weight Body Condition Chart for Dogs

To tell your dog`s body condition, first, look at your dog closely and observe which of its bones and structures are sticking out or not sticking out from under its skin. Next, use your hands to feel for fat and bones over your dog. To know which bones to look and feel for, check out the body condition tool guide from the World Small Animal Veterinary Association and this guide. This exercise will tell you the body condition score for your dog.

Body condition scores are from a scale of 1 to 9. A score of 1, 2 or 3 means that a dog is too skinny. A score of 4 or 5 means that a dog is of ideal weight, and a score above 5 means that a dog is overweight.

Talk to your vet if your Mastiff appears to be overweight. The vet might recommend reducing how much food to feed your Mastiff.

Conclusion on Mastiff Weight and Growth

In this article, we have provided you with the information, growth charts and growth calculators to help you tell how big your Mastiff will get. These tools will also help tell if your Mastiff is growing normally.

However, the best way to monitor and predict the growth of your Mastiff is to measure and record your puppy Mastiff`s weight every week.

Use our free Mastiff weight tracker and calculator tool available here to track and predict your Mastiff`s weight.

It is important that every Mastiff owner monitors the growth of their Mastiff for normal growth by checking the weight of their Mastiff regularly. Regular weight monitoring will let you detect any abnormal growth very early before it is too late. We discussed how you can tell if your Mastiff is growing normally from your Mastiff`s weight history earlier in this article.

Abnormal growth in Mastiff can be because of underlying disease (such are heart, hormonal, or bone problems) or because of overfeeding or underfeeding. All of the aforementioned reduce the Mastiff lifespan and quality of life.

Don`t wait. Start tracking your Mastiff`s weight today!