Mastiff (English Mastiff) vs Shih Tzu: Which Suits Your Home?

Few breed pairings on this site show a gap as extreme as this one: an English Mastiff can weigh up to 250 pounds, while a Shih Tzu tops out around 16 pounds — a ratio of more than fifteen to one. Height tells the same story, 27-32 inches for the Mastiff against 8-11 inches for the Shih Tzu, which stands roughly knee-high on most adults even fully grown. The Mastiff's sheer mass means furniture, doorways, and even simple things like turning around in a hallway all involve real physical space; the Shih Tzu can live comfortably in a space where a Mastiff's bed alone wouldn't fit.

Surprisingly, both breeds share identical low (2/5) ratings for both exercise need and general energy level — a rare point of agreement given how different they otherwise are. Neither the giant, laid-back Mastiff nor the small, calm Shih Tzu demands vigorous daily activity; short walks and indoor play satisfy both. The practical difference is what low-energy means at each scale: a Mastiff's brief walk still needs a strong leash-hand given its bulk, while a Shih Tzu's play session fits easily in a living room. For an owner who wants a genuinely low-exercise dog but hasn't decided on size, this metric offers no tiebreaker at all.

This is where the two breeds trade places entirely. The Mastiff needs only low (2/5) grooming and sheds moderately (3/5) thanks to a short, dense coat, while the Shih Tzu demands very high (5/5) grooming for its long, flowing coat despite shedding very low (1/5) — it's often marketed as relatively hypoallergenic for this reason. In practice, Shih Tzu owners typically need regular professional grooming appointments or serious at-home brushing skill to prevent painful mats, while Mastiff owners deal mainly with drool and periodic shedding rather than coat styling. Anyone with allergy concerns may lean Shih Tzu despite the higher grooming bill; anyone averse to brushing entirely may prefer the Mastiff's wash-and-go coat.

The Shih Tzu rates very high (5/5) for apartment suitability, the strongest score available, while the Mastiff rates low (2/5) — unsurprising given a 250-pound dog needs more than a one-bedroom to stretch out. Barking flips the expected pattern only slightly: the Mastiff is rated very low (1/5), among the quietest breeds in this comparison, while the Shih Tzu rates moderate (3/5). Both tolerate being alone at the same moderate (3/5) level. For a small apartment specifically, the Shih Tzu is the clear practical choice, though a quiet, undemonstrative Mastiff can work in a larger unit or house better than its size might suggest.

Both breeds land at moderate (3/5) for trainability, but their first-time-owner ratings split — Shih Tzu high (4/5), Mastiff low (2/5). That gap has less to do with intelligence and more with physical management: a stubborn 200-pound Mastiff that hasn't learned leash manners is a genuinely different challenge than a stubborn 12-pound Shih Tzu showing the same behavior. The Mastiff's calm, gentle, protective temperament makes it generally easygoing once trained, but its size means training consistency matters more, not less, for a beginner. The Shih Tzu's affectionate, playful nature is forgiving of training gaps precisely because the consequences of a missed command are so much smaller physically.

The Mastiff actually edges the Shih Tzu with kids, rated very high (5/5) against high (4/5), a testament to its famously gentle, patient temperament despite its intimidating size — supervision still matters given how easily its bulk alone could injure a small child by accident. The Shih Tzu pulls ahead with other dogs, high (4/5) versus the Mastiff's moderate (3/5), and both tie at moderate (3/5) with strangers. The Mastiff's protective instinct means it can be watchful rather than instantly welcoming toward unfamiliar visitors, while the Shih Tzu's outgoing, friendly nature tends toward more universal sociability, just expressed at a much smaller physical scale.

The Shih Tzu's lifespan of 10-16 years dramatically outpaces the Mastiff's 9-11, a gap typical of giant versus toy breeds. Both carry ten-item health lists, but the character differs: the Mastiff's includes cancer, bloat, dilated cardiomyopathy, and bone cancer — conditions tied to rapid giant-breed growth and size-driven strain on organs — while the Shih Tzu's list features brachycephalic obstructive airway syndrome, liver shunts, and eye problems, largely tied to its flat-faced, toy-breed conformation. Hip dysplasia and hypothyroidism appear on both lists despite the size difference. Prospective owners of either breed should ask breeders directly about health testing specific to these conditions before committing.

Cost level rates very high (5/5) for the Mastiff and high (4/5) for the Shih Tzu — both expensive, just for different reasons. The Mastiff's $150-$350 monthly and $2,200-$4,500 first-year costs are driven by enormous food volume and larger-dose medications; the Shih Tzu's $120-$250 monthly and $1,500-$3,000 first-year costs come mostly from grooming, given its very-high grooming-need rating and the professional appointments that typically requires. Neither breed is a budget option. An owner deciding between them on cost alone should weigh whether they'd rather pay for a large food bill or a recurring grooming bill, since both breeds land in the pricier half of this site's comparisons.