Small breed

Boston Terrier Growth Chart

Male adult weight12–25 lb

Female adult weight12–25 lb

Boston Terriers are compact, tuxedo-marked companions with a wide weight range depending on bone and muscle. They often finish growing near 10–12 months. Body shape helps interpret whether a puppy is toward the lighter or heavier end.

Expected Boston Terrier puppy weight at key ages (lb)
Age	Expected weight (low–high)
8 weeks	2.1–7.7 lb
12 weeks	3.3–10.1 lb
16 weeks	4.3–12.2 lb
20 weeks	5.2–14.2 lb
24 weeks	6.1–16 lb
32 weeks	7.8–19.5 lb
40 weeks	9.4–22.8 lb
1 year	10.9–25 lb

Boston Terrier Growth Stages

Understanding the typical growth stages helps you know what to expect as your Boston Terrier puppy grows.

Neonatal

0–2 weeks

Puppies are born with eyes and ears closed, relying entirely on their mother. Rapid weight gain occurs during this period.

Socialization

3–12 weeks

Eyes and ears open. Puppies begin to explore, play, and learn social behaviors. This is a critical period for development.

Juvenile

3–6 months

Rapid growth continues. Puppies become more independent, start teething, and develop coordination.

Adolescent

6–10 months

Growth rate begins to slow. Puppies reach sexual maturity and may test boundaries. Muscle mass develops.

Young Adult

10–12 months

Growth is nearly complete. Your puppy is filling out and approaching adult proportions.

Adult

12+ months

Your puppy has reached their full adult size. Weight should remain relatively stable with proper nutrition.

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How much will my Boston Terrier puppy weigh as an adult?

Adult Boston Terriers are classified as small dogs, with typical finished weights of 12 to 25 lb. Males may weigh 12–25 lb and females 12–25 lb. These are estimated ranges—individual genetics and parent size may shift results above or below breed norms.

At what age is a Boston Terrier fully grown?

Boston Terriers often finish near 10–12 months as small-breed companions. Overall, Boston Terriers—classified as small—usually mature between 9 and 12 months. Puppies may look nearly full-sized before muscle and bone fully settle, which is normal and expected for this breed.

How accurate is a Boston Terrier puppy weight chart?

A Boston Terrier puppy chart provides estimated trends rather than fixed outcomes. Real spread from wide bone and muscle range within the breed is normal, and markings and coat do not reflect actual frame size. Parent sizes and body condition may refine predictions when available.