Which is bigger, a Bullmastiff or a Mastiff?

By typical weight/height midpoints, the Mastiff tends to be larger overall. Bullmastiff typically weighs about 100-130 lbs (mid ~115 lbs) versus Mastiff at 120-230 lbs (mid ~175 lbs). Height at the shoulder is commonly listed around 24-27 inches vs 27-30 inches. Both are classified as large dogs in our data. On typical midpoints, Mastiff tends to be the larger dog.

Which is taller, Bullmastiff or Mastiff?

Mastiff is typically taller at the withers (24-27 inches vs 27-30 inches).

Which weighs more, Bullmastiff or Mastiff?

Mastiff usually weighs more (100-130 lbs vs 120-230 lbs).

Are Bullmastiff and Mastiff the same size class?

Yes—both are large in our breed data. Individuals still vary by sex and bloodline.

Do males and females change the size comparison?

Often yes. Males are commonly at the high end of weight/height ranges and females at the low end. Always check the actual dog (or parents) rather than breed averages alone.

Size matchup

Bullmastiff vs Mastiff: size & weight

Typical weight (100-130 lbs vs 120-230 lbs) and height (24-27 inches vs 27-30 inches)—so you can tell who’s bigger on the metrics that matter.

Mastiff typically larger

Bullmastiff

large · energy 3/5

100-130 lbs

Weight mid ~115 lbs

24-27 inches

Height mid ~25.5 in

Breed profile

Mastiff

large · energy 2/5

120-230 lbs

Weight mid ~175 lbs

27-30 inches

Height mid ~28.5 in

Breed profile

Bullmastiffs are large; English Mastiffs push further into giant mass—both need serious space and flooring.

Typical weight

Bullmastiff: 100-130 lbs (mid ~115 lbs)
Mastiff: 120-230 lbs (mid ~175 lbs)

Mastiff usually tips the scale higher.

Typical height (withers)

Bullmastiff: 24-27 inches (mid ~25.5 in)
Mastiff: 27-30 inches (mid ~28.5 in)

Mastiff is typically taller at the shoulder.

Size class & fit

Bullmastiff

large · lifespan 8-10 years

Gentle, Loyal, Protective

Mastiff

large · lifespan 6-10 years

Gentle, Calm, Loyal

Size drives food bills, car space, crate size, and how hard a jump lands on kids and seniors. Pair this page with lifestyle compare when temperament matters as much as inches.

Planning verdict

Lean Bullmastiff

Lean Bullmastiff if you want a large dog around 100-130 lbs and 24-27 inches, with energy 3/5.

Lean Mastiff

Lean Mastiff if you prefer large size near 120-230 lbs and 27-30 inches, with energy 2/5.

FAQs

Which is bigger, a Bullmastiff or a Mastiff?: By typical weight/height midpoints, the Mastiff tends to be larger overall. Bullmastiff typically weighs about 100-130 lbs (mid ~115 lbs) versus Mastiff at 120-230 lbs (mid ~175 lbs). Height at the shoulder is commonly listed around 24-27 inches vs 27-30 inches. Both are classified as large dogs in our data. On typical midpoints, Mastiff tends to be the larger dog.
Which is taller, Bullmastiff or Mastiff?: Mastiff is typically taller at the withers (24-27 inches vs 27-30 inches).
Which weighs more, Bullmastiff or Mastiff?: Mastiff usually weighs more (100-130 lbs vs 120-230 lbs).
Are Bullmastiff and Mastiff the same size class?: Yes—both are large in our breed data. Individuals still vary by sex and bloodline.
Do males and females change the size comparison?: Often yes. Males are commonly at the high end of weight/height ranges and females at the low end. Always check the actual dog (or parents) rather than breed averages alone.

Related size matchups

References

How to Choose the Right Dog Breed — American Kennel Club (AKC)
How Long Will Your Dog Live? Size Matters — American Kennel Club (AKC)
General Dog Care — ASPCA