How long does a Mastiff live?

The listed lifespan for a Mastiff is 6–10 years.

How tall is a Mastiff?

The listed height for a Mastiff is 30 in and up (male), 27.5 in and up (female).

Is a Mastiff good with children?

The AKC good-with-children score for a Mastiff is 5 out of 5.

When is a Mastiff full grown?

The growth size band for a Mastiff is up to 24 months.

Working Group

Mastiff

Mastiff is a giant dog in the Working Group. Adult weight is 160–230 lb (male), 120–170 lb (female), height is 30 in and up (male), 27.5 in and up (female), and the listed lifespan is 6–10 years. AKC describes the temperament as Dignified, Good-natured, Courageous.

Last reviewed November 1, 2026.

Lifespan6–10 years

Weight160–230 lb (male), 120–170 lb (female)

SizeGiant GroupWorking Group

Height

30 in and up (male), 27.5 in and up (female)

Energy

3 / 5

Shedding

3 / 5

Grooming

1 / 5

Trainability

3 / 5

Good with kids

5 / 5

The breed record

Across 36 single-size giant breeds, a lifespan midpoint of 8 years is about 2.2 years shorter than the 10.2-year average. A midpoint adult weight of 175 lb is about 59 lb heavier than the 116 lb average for those giant breeds.

The listed origin is England. The coat is described as double, short. The AKC energy score is 3 out of 5, 0.7 points below the group average of 3.7 for the Working Group. Shedding scores 3 out of 5. Grooming scores 1 out of 5, so home brushing covers most weeks. Trainability scores 3 out of 5. Good with children scores 5 out of 5. Good with other dogs scores 3 out of 5. AKC ranked this breed number 40 in 2025.

Adult size is usually reached in up to 24 months (size-band statement (Salt et al. 2017): larger breeds require up to 24 months). AKC parent-club recommended health screenings: Patella Evaluation, Hip Evaluation, Elbow Evaluation, Cardiac Exam, Ophthalmologist Exam, Cystinuria DNA Test, Autoimmune Thyroiditis, Dominant Progressive Retinal Atrophy (dPRA) (Bullmastiff/Mastiff Type) DNA Test, Degenerative Myelopathy (Common Variant) (DM) - DNA Test, and Canine Multifocal Retinopathy Type 1 (CMR) DNA Test. These are screening tests, not a list of diseases the breed is guaranteed to develop.

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