Boston Terrier puppy weight chart
The ranges below run from a puppy that will end up at the light end of the breed (12 lb) to one heading for the heavy end (25 lb). Males usually track the upper numbers and females the lower.
| Age | Weight (lb) | Weight (kg) | % of adult |
|---|---|---|---|
| 8 weeks | 2.9 to 6 | 1.3 to 2.7 | 24% |
| 10 weeks | 3.7 to 7.8 | 1.7 to 3.5 | 31% |
| 12 weeks | 4.6 to 9.5 | 2.1 to 4.3 | 38% |
| 14 weeks | 5.4 to 11 | 2.4 to 5 | 45% |
| 16 weeks | 6.2 to 13 | 2.8 to 5.9 | 52% |
| 5 months | 8.2 to 17 | 3.7 to 7.7 | 68% |
| 6 months | 9.3 to 19 | 4.2 to 8.6 | 77% |
| 7 months | 10 to 21 | 4.5 to 9.5 | 84% |
| 8 months | 11 to 22 | 5 to 10 | 90% |
| 9 months | 11 to 23 | 5 to 10 | 93% |
| 10 months | 11 to 24 | 5 to 11 | 96% |
| 12 months | 12 to 25 | 5.4 to 11 | 99% |
| 15 months | 12 to 25 | 5.4 to 11 | 100% |
How Boston Terriers grow
Cheerful "American gentleman" in a tuxedo coat. As a small breed, a Boston Terrier is roughly half grown at about 16 weeks and reaches adult size at around 10 to 14 months. Boston Terriers are shown in three weight classes: under 15 lb, 15 to 20 lb and 20 to 25 lb.
Small and medium puppies have fast metabolisms. Split their food into 3 or 4 meals a day until about 4 months old, then move to 2 or 3 meals.
Is my Boston Terrier puppy underweight or overweight?
The scale only tells half the story. Check your puppy's body condition: you should be able to feel the ribs easily under a thin layer of fat, and see a waist when you look down from above. A puppy that tracks low on the chart but has good energy and body condition is usually just going to be a smaller adult. Talk to your vet if your puppy stops gaining for more than two weeks, loses weight, or has persistent diarrhea.
Frequently asked questions
How big will my Boston Terrier puppy get?
Most Boston Terriers finish at 12 to 25 lb. Enter your puppy’s age and weight in the calculator above for a personal estimate.
When does a Boston Terrier stop growing?
Most Boston Terriers reach adult height and weight at around 10 to 14 months.
How much should a Boston Terrier puppy weigh at 12 weeks?
Usually around 4.6 to 9.5 lb, which is about 38% of adult weight. Lighter or heavier can still be normal if your vet is happy with your puppy’s body condition.