Use this Spanish Mastiff puppy weight calculator to predict how big your puppy will get. Spanish Mastiffs are a giant livestock-guardian breed that keeps growing until around 24-36 months.
Enter your puppy's current weight and age to predict their adult size
Estimates based on breed growth curves. Individual dogs vary with genetics and nutrition — check with your vet for a personalized read.
Slows fast eaters, can aid digestion, holds 4 cups dry or wet food — sized for giant breeds.
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| Age | Weight |
|---|---|
| Birth | 3 to 7 lbs |
| 2 Months | 11 to 20 lbs |
| 3 Months | 21 to 40 lbs |
| 4 Months | 35 to 60 lbs |
| 5 Months | 49 to 80 lbs |
| 6 Months | 63 to 100 lbs |
| 7 Months | 77 to 120 lbs |
| 9 Months | 91 to 140 lbs |
| 10 Months | 105 to 160 lbs |
| 1 Year | 119 to 180 lbs |
| 1.5 Years | 133 to 200 lbs |
| 2 Years | 140 to 200 lbs |
Estimated from typical giant-breed growth curves and the Spanish Mastiff's adult weight range. Individual puppies vary — use the calculator above for a prediction based on your puppy's actual current weight.
New breed data, growth tips, and puppy-parenting insights, plus our free printable puppy growth tracker.
Prone to hip and elbow dysplasia given the breed's giant size; as a deep-chested breed, bloat risk also applies.
A large-breed puppy formula through the (notably slow) growth period; adults do well on a quality diet with portion control.
The dense double coat sheds moderately and needs regular brushing.
Independent and protective by design — early socialization and an experienced handler matter given the breed's giant size and guarding instincts.
A massive Spanish livestock-guardian breed with roots dating back to Roman times, historically used to protect sheep flocks from wolves during seasonal migrations.
Calm and protective, Spanish Mastiffs are gentle with family but serious, independent guardians by design.
