Updated · Published by Radif Partners
Bullmastiff Weight & Growth Chart
Complete weight guide with growth charts for male and female Bullmastiffs from puppy to adult.
The Bullmastiff belongs to the Working group and originates from England. Adults typically weigh between 100 and 130 pounds, standing 24 to 27 inches at the shoulder. Life expectancy runs from 7 to 9 years, and the figures on this page describe that range rather than a single average, because the spread is what matters when you are deciding. Running costs settle around $235 a month once the dog is past puppyhood, before insurance and before anything unexpected. These numbers come from published breed standards and, where a standard is silent, from longevity and veterinary studies; they describe the breed as a population and not the dog in front of you. Line, upbringing, early socialisation and simple chance move an individual well away from the typical profile, and two dogs of the same breed often differ more than two dogs of different breeds. Nothing here is a diagnosis: for a specific animal, a veterinary surgeon who has examined it will always know more than a table.
Bullmastiff Weight Overview
Adult Bullmastiffs typically weigh between 100 and 130 pounds, with males generally being larger than females. Males average 100–130 lbs while females typically weigh 85–114 lbs.
Males weigh 110-130 pounds, females 100-120 pounds; the breed should be powerfully built but not excessively heavy or lacking in agility..
Bullmastiff Growth Chart
When Does a Bullmastiff Stop Growing?
The Bullmastiff stops growing in height (target: 24–27 inches) around 15–24 months of age, but may continue adding weight toward 130 lbs for several more months. Males weigh 110-130 pounds, females 100-120 pounds; the breed should be powerfully built but not excessively heavy or lacking in agility..
Early spay/neuter can affect growth plate closure, potentially resulting in a slightly taller but leaner adult.
Bullmastiff Male vs Female Size Differences
Male and female Bullmastiffs differ noticeably in size, a pattern common in giant breeds. Males typically weigh 100–130 lbs, while females weigh 85–114 lbs. Both sexes stand 24–27 inches tall at the shoulder, though males tend to fall at the upper end of this range.
These size differences can influence practical ownership decisions. Larger males require more food, larger crate sizes, and stronger leash handling. Female Bullmastiffs at the lower weight range may be easier to manage physically for smaller handlers or families with children. Both sexes share the same temperament and health profile, so size preference should be a practical decision rather than a temperament-based one.
Is My Bullmastiff Overweight?
Assessing your Bullmastiff's body condition (healthy range: 100–130 lbs):
- Rib check: Run your hands along the ribcage, you should feel individual ribs under a slight fat layer
- Overhead view: A defined waist should be visible between ribs and hips
- Side profile: The abdomen should tuck upward behind the last rib
Overweight Bullmastiffs face higher risks of Lymphoma, joint problems, and shortened lifespan. As a giant-sized working breed, maintaining lean body condition is especially important for longevity. Work with your vet to adjust feeding and exercise if needed.
Bullmastiff Weight Management Tips
Maintaining your Bullmastiff at a healthy weight between 100 and 130 lbs is one of the most impactful things you can do for their long-term health. Studies consistently show that lean dogs live an average of 1.8–2.5 years longer than overweight dogs of the same breed.
Portion control: Use a measuring cup for every meal rather than estimating. Feed the amount recommended for your Bullmastiff's ideal weight, not their current weight if they are overweight. Divide daily food into two meals for adults and three meals for puppies under six months.
Treat management: Treats should not exceed 10% of daily caloric intake. Use small, low-calorie training treats and consider using pieces of your dog's regular kibble as rewards during training sessions. Avoid table scraps entirely, as they add unpredictable calories and can introduce foods that are toxic to dogs.
Exercise alignment: With an exercise needs rating of 2/5, the Bullmastiff requires lighter exercise. Even with lower activity needs, daily movement is important for maintaining muscle tone and healthy weight. Short walks and play sessions help prevent the gradual weight creep that affects less active breeds.
Regular weigh-ins: Weigh your Bullmastiff monthly and track the trend. Gradual weight gain of even one to two pounds per month can lead to significant obesity over time. Your veterinarian can establish your dog's ideal weight during wellness visits and recommend caloric adjustments as needed.
Feeding Recommendation
Plan on 1.5–2.6 cups of premium dry food daily for your adult Bullmastiff, divided into morning and evening meals. Given this working breed's predisposition to Lymphoma, discuss dietary approaches that may help manage this risk with your vet. Males weigh 110-130 pounds, females 100-120 pounds; the breed should be powerfully built but not excessively heavy or lacking in agility..
Bullmastiff Weight by Age Table
The following table shows expected weight ranges for male and female Bullmastiffs at key developmental milestones. Individual dogs may fall slightly outside these ranges depending on genetics, nutrition, and activity level. Consult your veterinarian if your Bullmastiff's weight deviates significantly from these benchmarks.
| Age | Male (lbs) | Female (lbs) |
|---|---|---|
| 3 months | 23.8–28.2 | 20.1–24.1 |
| 6 months | 53.4–63.6 | 45.3–54.1 |
| 9 months | 77.2–91.8 | 65.4–78.2 |
| 12 months | 95.0–113.0 | 80.5–96.3 |
| 18 months | 112.8–134.2 | 95.6–114.3 |
| 24 months | 118.8–141.2 | 100.7–120.3 |
Health Risks of Incorrect Weight in Bullmastiffs
Both underweight and overweight conditions pose serious health risks for the Bullmastiff. Understanding these risks reinforces the importance of maintaining your dog within the 100–130 lb target range.
Overweight risks: Excess weight places additional strain on joints, increasing the risk and severity of conditions like Lymphoma. Overweight Bullmastiffs also face higher rates of diabetes, heart disease, respiratory compromise, heat intolerance, and reduced lifespan. Even moderate excess weight, just 10–15% above ideal, shortens life expectancy and reduces quality of life.
Underweight risks: A Bullmastiff consistently below 100 lbs may be experiencing inadequate nutrition, parasitic infection, dental problems that prevent eating, or underlying illness. Underweight dogs have weakened immune systems, poor coat quality, reduced energy, and slower healing. If your Bullmastiff appears thin despite normal feeding, veterinary examination is essential to rule out medical causes.
Frequently Asked Questions
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