How big will my Bullmastiff get?
An adult Bullmastiff weighs 110 to 130 pounds for males and 100 to 120 pounds for females (49.9 to 59 kg for males and 45.4 to 54.4 kg for females), according to the American Kennel Club. Put in your puppy’s age and weight to see where they’re heading.
Bullmastiff puppy weight calculator
Bullmastiff adult weight
| Pounds | Kilograms | |
|---|---|---|
| Male | 110 to 130 pounds | 49.9 to 59 kg |
| Female | 100 to 120 pounds | 45.4 to 54.4 kg |
Adult weight from the American Kennel Club’s Bullmastiff breed page, checked 1 October 2026. Individual dogs vary, and a healthy weight for your dog is one for your vet to judge.
How the estimate works
The calculator takes your puppy’s weight, divides it by their age in weeks, and multiplies by 52. It’s a quick guide, not a growth chart: puppies gain fast early on and slow down as they near adult size, so the answer shifts as they grow. That’s why the result is shown next to the breed’s adult weight. If the two disagree, trust the breed’s weight and your vet.
More on the Bullmastiff
- Ask other owners on the forum how their Bullmastiff grew.
- Find a dog trainer near you, ranked by Bark Score with training methods labelled.
- Dog age calculator: your dog’s age in human years.