Behavior
Which breed is the better overall pick?
The Aussie suits an active household with room to run; the Mastiff suits a calmer home that wants a large, gentle presence and can absorb higher costs.
Australian Shepherd vs Mastiff (English Mastiff): Which Suits Your Home?
Australian Shepherd or Mastiff (English Mastiff)? On paper they differ most on exercise need, and on the scales Mastiff (English Mastiff) is the heavier at 120–250 lbs. Here is how the two compare on everything that shapes an ordinary week.
This is for someone already down to Australian Shepherd and Mastiff (English Mastiff) and deciding between them. For this pair the decision usually turns on exercise need and energy level, so those are covered first and in most detail. Anyone choosing from a flat has a clear answer here: Mastiff (English Mastiff) rates 2/5 against 1/5. There is no origin story here — only what changes about your week.
Quick verdict
Between Australian Shepherd and Mastiff (English Mastiff), exercise need is what separates them, and Mastiff (English Mastiff) is the lower-effort dog of the two to keep.
Choose australian shepherd if...
Choose Australian Shepherd if you already have another dog, you want a dog that picks up training quickly and a smaller dog suits your car, your home or your back.
Choose mastiff if...
Choose Mastiff (English Mastiff) if you do not want a standing grooming appointment, shedding is a problem in your house and your walking routine is modest.
Head-to-head comparison
| Feature | australian shepherd | mastiff | Winner |
|---|---|---|---|
| Size class | medium | giant | Equal |
| Weight | 40–65 lbs | 120–250 lbs | Equal |
| Height | 18–23 in | 27–32 in | Equal |
| Lifespan | 12–15 years | 9–11 years | australian shepherd |
| Exercise need | Very high (5/5) | Low (2/5) | mastiff |
| Grooming need | Moderate (3/5) | Low (2/5) | mastiff |
| Shedding | High (4/5) | Moderate (3/5) | mastiff |
| Energy level | Very high (5/5) | Low (2/5) | Equal |
| Barking | Moderate (3/5) | Very low (1/5) | mastiff |
| Apartment suitability | Very low (1/5) | Low (2/5) | mastiff |
| Good for first-time owners | Low (2/5) | Low (2/5) | Equal |
| Tolerates being alone | Low (2/5) | Moderate (3/5) | mastiff |
| Trainability | Very high (5/5) | Moderate (3/5) | australian shepherd |
| Good with kids | High (4/5) | Very high (5/5) | mastiff |
| Good with other dogs | High (4/5) | Moderate (3/5) | australian shepherd |
| Friendly to strangers | Low (2/5) | Moderate (3/5) | mastiff |
| Cost level | Moderate (3/5) | Very high (5/5) | australian shepherd |
| Coat | Medium-length double coat | Short, dense | Equal |
| Origin | United States | England | Equal |
| Typical monthly cost | $100–$200 | $150–$350 | Equal |
| Typical first-year cost | $1,500–$2,800 | $2,200–$4,500 | Equal |
Deep dive
Size and build
Weight is the whole story in this comparison. The Aussie sits in a 40-65 lb range; the English Mastiff runs 120-250 lbs, meaning the largest Mastiffs weigh close to four times what the largest Aussies do. Height is also lopsided, 27-32 inches for the Mastiff against the Aussie's 18-23.
Energy and exercise
The Aussie rates 5/5 for exercise need, the Mastiff a low 2/5, a genuine mismatch in daily activity expectations. Mastiffs are famously low-key for their size, more interested in guarding a doorway than running a field, so don't expect that huge frame to translate into a demanding exercise routine.
Grooming and shedding
Grooming favors the Mastiff slightly, 2/5 against the Aussie's 3/5, thanks to a short dense coat. Shedding tips toward the Aussie instead, 4/5 versus the Mastiff's moderate 3/5, a surprising result given the Mastiff's size, since more surface area doesn't automatically mean more hair on your floor.
Apartment living, noise and time alone
Neither breed suits apartment living, 2/5 for the Mastiff, 1/5 for the Aussie, and a 250-lb dog in a small unit brings its own set of practical problems beyond the rating. Barking favors the Mastiff heavily, a near-silent 1/5 against the Aussie's moderate 3/5, and the Mastiff also tolerates being alone slightly better (3/5 vs 2/5).
Training and owner experience
Trainability favors the Aussie clearly, 5/5 against the Mastiff's moderate 3/5, and both rate a low 2/5 for first-time owners. The Mastiff's challenge isn't intelligence so much as sheer physical management, a stubborn 200-lb dog that hasn't learned leash manners is a genuinely different problem than a stubborn 50-lb one.
Kids, other dogs and visitors
The Mastiff rates higher with kids (5/5 vs 4/5) and with strangers (3/5 vs 2/5), fitting the breed's reputation as a gentle, patient giant despite its guarding instincts. The Aussie edges ahead with other dogs, 4/5 against the Mastiff's 3/5.
Health and lifespan
Lifespan clearly favors the Aussie, 12-15 years against the Mastiff's 9-11, a real gap tied directly to the Mastiff's size. Both breeds share hip dysplasia, elbow dysplasia, cancer, progressive retinal atrophy and hypothyroidism, and the Mastiff's list adds bloat, dilated cardiomyopathy and bone cancer risks common to giant breeds.
Cost to keep
Cost level rates 5/5 for the Mastiff against the Aussie's 3/5, and the dollar figures back it up hard, $150-350 monthly against $100-200, with first-year costs of $2,200-4,500 versus $1,500-2,800. Feeding a 200-plus-lb dog alone puts the Mastiff in a different cost bracket.
Australian Shepherd vs Mastiff (English Mastiff) at a glance
Australian Shepherd weighs 40–65 lbs and lives 12–15 years; Mastiff (English Mastiff) weighs 120–250 lbs and lives 9–11 years. The two diverge most on exercise need, energy level and barking and 2 other rated axes. Almost every rated axis separates them at least slightly. Where the table declares a winner it means less work for the owner, nothing more; descriptive rows are left as ties on purpose. The value here is in the differences between the two columns; treat any single score as approximate.
Frequently asked questions
How much does a Mastiff outweigh an Aussie?
Substantially, a Mastiff can reach 250 lbs against the Aussie's 65 lb ceiling, roughly a four-to-one difference at the top end of each range.
Does the Mastiff's size mean it needs more exercise?
No, it's the opposite. The Mastiff rates just 2/5 for exercise need against the Aussie's 5/5, one of the more counterintuitive results in this comparison.
Which breed barks less?
The Mastiff, by a lot, 1/5 against the Aussie's 3/5. It's a notably quiet breed for its size.
How much more does the Mastiff cost to keep?
Considerably more, $150-350 monthly against the Aussie's $100-200, and $2,200-4,500 versus $1,500-2,800 in the first year, largely driven by food volume.
Do the breeds share health conditions?
Yes, several, hip dysplasia, elbow dysplasia, cancer, progressive retinal atrophy and hypothyroidism appear on both lists, with the Mastiff adding size-linked risks like bloat.
Which breed lives longer?
The Aussie, by a few years, 12-15 versus the Mastiff's 9-11.
Is either breed suited to a first-time owner?
Not really, both rate 2/5. The Aussie needs a job to stay settled; the Mastiff needs an owner confident handling its sheer size and weight.
Quick answers
View more answersCosts
How much more expensive is the Mastiff monthly?
Noticeably more, $150-350 against the Aussie's $100-200.
Training
Which breed actually needs more exercise?
The Aussie, rated 5/5 against the Mastiff's 2/5, size doesn't predict activity level here.
Health
Which breed has the shorter lifespan?
The Mastiff, at 9-11 years against the Aussie's 12-15.
Related DogBreedCompass guides
- Australian Shepherd breed guide – Readers comparing the two usually want the full profile of Australian Shepherd before deciding.
- Mastiff (English Mastiff) breed guide – The same for Mastiff (English Mastiff), so the comparison can be checked against the detail.
- Australian Shepherd vs German Shorthaired Pointer – German Shorthaired Pointer is the closest breed to Australian Shepherd on the measured axes, so it is the natural next comparison.
- Mastiff (English Mastiff) vs Saint Bernard – Saint Bernard sits closest to Mastiff (English Mastiff), which makes it the alternative worth ruling out.
- Australian Shepherd vs Saint Bernard – Saint Bernard is the other breed Mastiff (English Mastiff) is most often weighed against.
- Mastiff (English Mastiff) health problems – The health pages set out what each breed is actually screened for.
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Important reminder
Health information here is general and is not veterinary advice. If your dog shows pain, sudden behaviour change, or worsening symptoms, consult a licensed veterinarian.
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