Bullmastiff Weight & Growth Chart

Complete weight guide with growth charts for male and female Bullmastiffs from puppy to adult.

Male Adult Weight
100–130 lbs
Female Adult Weight
85–114 lbs

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.

Weight can vary based on genetics, diet, exercise level, and whether the dog has been spayed or neutered. The growth chart below shows the typical weight progression from puppy to adult.

Growth Chart

When Does a Bullmastiff Stop Growing?

Bullmastiffs typically reach their full adult height by 15 to 24 months and their full adult weight shortly after. This breed may continue to fill out and add muscle mass for several months after reaching full height.

Factors that influence when a Bullmastiff stops growing include genetics, nutrition, and spay/neuter timing. Dogs that are spayed or neutered very early may grow slightly taller due to delayed growth plate closure.

Is My Bullmastiff Overweight?

To determine if your Bullmastiff is at a healthy weight:

  • Rib test: You should be able to feel the ribs without pressing hard, with a thin layer of fat covering them
  • Waist check: Viewed from above, there should be a visible waist behind the ribs
  • Tuck-up: From the side, the abdomen should tuck up behind the rib cage

If your Bullmastiff is overweight, work with your veterinarian to develop a safe weight loss plan. Even a 10% reduction in body weight can significantly improve health outcomes.

Feeding Recommendation

Adult Bullmastiffs typically need 1.5 to 2.6 cups of high-quality dry food per day, divided into two meals. Puppies need more frequent feedings — three to four times daily until six months, then twice daily. Always provide fresh water and adjust portions based on activity level and body condition.

Weight by Age Table

AgeMale (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

Frequently Asked Questions

Adult Bullmastiff weight varies by gender and individual build. Refer to the weight ranges above and consult your vet to determine your specific dog's ideal weight.
Most Bullmastiffs reach their adult weight between 12 and 24 months, depending on their size category. Larger dogs take longer to reach full size.
You should be able to feel your Bullmastiff's ribs without pressing hard, and they should have a visible waist when viewed from above. Your vet can provide a body condition score.
Feeding amounts depend on your puppy's age, current weight, and expected adult size. Follow the food manufacturer's guidelines and adjust based on your vet's recommendations.
If your Bullmastiff puppy isn't gaining weight as expected, consult your veterinarian. Common causes include parasites, inadequate nutrition, or underlying health conditions.