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Boston Terrier growth chart
How much should a Boston Terrier puppy weigh? Find the row that matches your puppy's sex and expected adult weight, and read across by age.
Boston Terrier puppy weight chart (lb)
| Adult weight | 2 mo | 3 mo | 4 mo | 5 mo | 6 mo | 8 mo | 10 mo | 12 mo |
|---|---|---|---|---|---|---|---|---|
| Adult, 12 lb | 2.9 | 4.7 | 6.5 | 8.1 | 9.4 | 11 | 12 | 12 |
| Adult, 25 lb | 6.1 | 9.9 | 14 | 17 | 20 | 23 | 24 | 25 |
Boston Terrier puppy weight chart (kg)
| Adult weight | 2 mo | 3 mo | 4 mo | 5 mo | 6 mo | 8 mo | 10 mo | 12 mo |
|---|---|---|---|---|---|---|---|---|
| Adult, 5.4 kg | 1.3 | 2.2 | 3.0 | 3.7 | 4.2 | 4.9 | 5.2 | 5.4 |
| Adult, 11 kg | 2.8 | 4.5 | 6.2 | 7.6 | 8.8 | 10 | 11 | 11 |
Typical weights by month. Individual puppies often sit 10–15% above or below these numbers. Last reviewed October 7, 2026.
How big does a Boston Terrier get?
According to the American Kennel Club's breed profile for the Boston Terrier, adults weigh: male & female 12–25 lb. Life expectancy is 11–13 years.
| Weight | Height | |
|---|---|---|
| Male & female | 12–25 lb | 10–12 in |
When does a Boston Terrier stop growing?
Boston Terriers grow like other small-sized dogs: they are close to adult weight at around 11 months. At 6 months a typical Boston Terrier puppy has reached about 78% of its adult weight.
To estimate your own puppy's adult weight from its current weight and age, use the puppy weight calculator and choose "Small" as the expected adult size.
How the chart is made
The adult weights come from the AKC breed profile. The weight at each month is estimated with our small-breed growth curve, which gives the share of adult weight a typical puppy of that size reaches at each age. The curves are simplified from published research on dog growth, including the growth standard charts by Salt and colleagues (PLOS ONE, 2017).
If your puppy is well below or above the chart, stops gaining weight, or looks very thin or round, ask your vet to check its body condition.
Questions people ask
How much should a 3-month-old Boston Terrier weigh?
Typically about 4.7–9.9 lb, depending on sex and how big the dog will be as an adult.
How much should a 6-month-old Boston Terrier weigh?
Typically about 9.4–20 lb, roughly 78% of adult weight.
When is a Boston Terrier full grown?
Most Boston Terriers are close to their adult weight at around 11 months, though many keep filling out with muscle for a while after that.
How big will my Boston Terrier get?
The AKC lists adult weights of male & female 12–25 lb. Your puppy's parents are a good guide to where in that range it will end up.