Bullmastiff vs Mastiff

A Bullmastiff
Photo: Maja Dumat
A Mastiff
Photo: ocean yamaha

Side by side

Bullmastiff
Mastiff
Adult weight
Males 50–59 kg (110–130 lb); females 41–50 kg (90–110 lb)1
Males 73–104 kg (160–230 lb); females 54–77 kg (120–170 lb) (breed club figure)2
Height
No sourced figure
Males 70–77 cm; females 70–77 cm3
Lifespan
Median 10.2 years4
Median 9 years4
Fully grown
13 months, both sexes5
15 months, both sexes5
Group
Pinschers & molossoids6
Pinschers & molossoids7
Coat
Short coat6
Short coat7
Shedding
Sheds through the year
Grooming
A brush once a week
Exercise
A moderate amount
Health
Blood-vessel cancer of the skin (far more likely); Inward-rolling eyelid (far more likely)8,9
Bone cancer (far more likely); Blood-vessel cancer of the skin (far more likely)8
Class
Watchdog
Watchdog

Which suits you

Size
The Mastiff is larger on average: about 77 kg (170 lb) as an adult, against 50 kg (110 lb) for the Bullmastiff.
Lifespan
In UK vet records the Bullmastiff lives longer: a median of 10.2 years, against 9 for the Mastiff.
Temperament
They differ most on affection (Bullmastiff: a lap or leaning dog; Mastiff: affectionate on its own terms) and on independence (Bullmastiff: decides for itself; Mastiff: cooperative, with its own ideas).
Alike
Both are rated the same on loyalty: sticks close to its people.
Neither is the better dog in general. Which suits you depends on your home, your days and the care you can give.
Take the breed matcher

What they're like

Bullmastiff
Pinschers & molossoids · Giant

Bullmastiffs are calm, steady and devoted to their household, and reserved and watchful with strangers.

Mastiff
Pinschers & molossoids · Giant

By nature it is calm, dignified and good-natured with its household, while staying watchful and reserved with strangers. It tends to guard by its presence rather than by aggression.

The Bullmastiff page →The Mastiff page →

Breed traits

Day to day
Bullmastiff
Mastiff
Activity
Happy with modest walks
Happy with modest walks
Intelligence
Easy-going, simple routines
Easy-going, simple routines
Handler demand
Differs
Needs an experienced owner
Needs steady training
With people
Bullmastiff
Mastiff
Affection
Differs
A lap or leaning dog
Affectionate on its own terms
Loyalty
Sticks close to its people
Sticks close to its people
Independence
Differs
Decides for itself
Cooperative, with its own ideas
Around the home
Bullmastiff
Mastiff
Sensitivity
Hardy, takes a busy home in its stride
Hardy, takes a busy home in its stride
Voice
Quiet
Quiet
Prey drive
Differs
Chases; needs managing
Usually fine with small pets
Breed explains only about 9% of how individual dogs differ in behaviour10. Meet the dog. A good breeder breeds for temperament as well as health, and matches each puppy's personality to the right home11,12.

Puppy growth

Reference curves · both sexes
The Mastiff grows to the heavier adult, about 79 kg against the Bullmastiff's 50 kg.
Bullmastiff
Mastiff
0501001502m4m6m9m12m18m
0501001502m3m4m6m9m12m18m

More comparisons

Compare the Bullmastiff with
Bullmastiff vs RottweilerMastiff vs Saint BernardGreat Dane vs MastiffCane Corso vs MastiffAll breed comparisons →

Sources

Parts of this page were written by AI ·