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Boston Terrier Growth: Height, Weight, and Growth Chart

Boston Terriers’ growth rates vary from dog to dog, but they are typically fully grown after 10 to 14 months. The average weight of an adult Boston Terrier varies between 10 and 25 pounds, while their height varies between 15 and 17 inches.

Boston Terriers experience five growth stages: 

  • Neonatal
  • Transitional
  • Socialization
  • Juvenile
  • Adolescence

During these stages, they develop differently. 

It is essential to handle each stage correctly to help your Boston Terrier grow into a healthy adult. It also helps to reduce anxieties, behavioral issues, and other problems.

This article explores each developmental stage of Boston Terriers and why Boston terriers behave the way they do during every stage.

How Tall Do Boston Terriers Get?

Adult Boston Terriers are between 15 and 17 inches tall (38.1 to 43.2 centimeters). They are considered to be small to medium-sized dogs. Dogs below 22 inches are considered small, while all others are medium-sized.

How Tall Do Boston Terriers Get

How Much Do Boston Terriers Weigh?

Fully grown Boston Terriers weigh between 10 and 25 pounds (4.5 and 11.3 kilograms). Females weigh less than males. Adult males weigh between 15 and 25 pounds, while females weigh between 10 and 20 pounds.

As small to medium-sized dogs, Boston Terriers don’t weigh a lot. Most people can pick them up without issues.

Their weight does fluctuate, depending on several factors:

  • Genetics
  • Nutrition
  • Physical activity
  • Exercise 

Read More: Boston Terrier Size Charts

Boston Terrier Weight Chart

Boston Terriers’ average weight differs depending on their age. Their growth is incremental and is more noticeable during their first months. Boston Terriers weigh 0.48 pounds on average when they are born and reach 23.17 pounds when they are one year old.

This table illustrates the average weight of Boston Terriers, by age.[1]

Age Weight In PoundsWeight In Kilograms
0 (Birth)0.48 lbs0.22 kg
1-month-old Boston Terrier2.53 lbs1.15 kg
2-month-old Boston Terrier4.40 lbs2.00 kg
3-month-old Boston Terrier6.61 lbs3.00 kg
4-month-old Boston Terrier8.81 lbs4.00 kg
5-month-old Boston Terrier12.12 lbs5.50 kg
6-month-old Boston Terrier14.33 lbs6.50 kg
7-month-old Boston Terrier16.09 lbs7.30 kg
8-month-old Boston Terrier19.84 lbs9.00 kg
9-month-old Boston Terrier20.94 lbs9.50 kg
10-month-old Boston Terrier21.29 lbs9.75 kg
11-month-old Boston Terrier22.05 lbs10.00 kg
12-month-old Boston Terrier23.17 lbs10.50 kg

Boston Terrier Puppy Development Stages

Boston Terriers go through different growth stages, similar to humans. During each stage, they experience different emotional and physical changes.

This table lists the 5 development stages of Boston Terriers.

Growth StagePeriod
Neonatal stage0 – 2 weeks
Transitional period2 – 3 weeks
Socialization period3 – 12 weeks
Juvenile period3 – 6 months
Adolescence6 – 18 months

1. The Neonatal Stage

Boston Terriers Neonatal Stage
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The Boston Terrier neonatal stage represents the period between birth and 2 weeks of age. Most people buy their Boston Terriers after they have gone through this stage. The breeder’s puppy care at this stage directly influences the dogs’ well-being later on in life.

The neonatal stage comes with high mortality rate. This risk of death is increased during birth and the first days after. Many puppies die during this period due to bacterial infections.

Many issues[2] can lead to bacterial infections and death:

  • Hypoglycemia or low blood sugar
  • Respiratory distress
  • Dehydration
  • Hypothermia 
  • Congenital abnormalities

Physical Developments

During the neonatal stage, Boston Terrier puppies are blind, deaf, and lack teeth. They also lack basic motor skills.

As a result, they crawl and are not able to move far away from their spot.

Boston Terrier puppies open their eyes when they are 10 days old, but still can’t see.

Emotional Developments

Boston Terriers rely on their mother during the neonatal stage. They need to feel secure, even if all they do is sleep and eat all day.

Boston Terriers detect their mothers using their bodies, despite their blindness. They panic and cry when they can’t find her. 

If Boston Terrier puppies are separated from their mothers during the neonatal stage, they become anxious. This early anxiety can leave marks throughout their adult life. This can be a cause of behavior issues later on in life.

Growth and Weight Gain

Boston Terriers puppies experience their fastest growth during this stage. 

It is essential for owners to monitor their puppies’ weight since birth. Low birth weight is correlated with higher mortality rates during the neonatal stage.[3]

Care Tips for the Neonatal Stage 

During the neonatal stage, it is essential to:

  • Not separate the puppies from their mothers.
  • Make sure their space is clean.
  • Observe if the mother doesn’t take care of one of the puppies and substitute her role if this is the case.
  • Make sure the puppies are warm and eat well.
  • Detect any signs of respiratory issues or congenital defects.

2. Transitional Stage

Boston Terriers Transitional Stage
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The Boston Terrier transitional stage takes place when they are 2 to 3 weeks of age. During this period, Boston Terriers begin developing their senses, such as their sense of smell and hearing. 

Physical Developments

During the transitional period, Boston Terrier puppies begin to see. They are fun to watch while they start exploring their surroundings. 

The puppies start moving on their own and can pee and defecate in a separate place. 

Their ear canals are open and they begin noticing the sounds around them. Their teeth also start growing out, and they will start biting, though it doesn’t hurt.

Emotional Developments

Boston Terrier puppies begin to notice their siblings and start developing their social skills. 

They will play and wag their tails. Some even start growling. These activities are forms of early social behavior.

Growth and Weight Gain

Boston Terriers eat more and gain weight fast during this period. Their nutritional needs increase and they can start eating dog food, depending on their teeth development.

Care Tips for the Transitional Stage 

Do the following during Boston Terriers’ transitional stage:

  • Start feeding them wet food from a bowl.
  • Introduce them to drinking water from a bowl.
  • Allow their mother to feed them because this is their main feeding reliance at this age.

3. Socialization Stage

Boston Terrier Socialization Stage

Boston Terriers are in their socialization stage between ages 3 and 12 weeks[4]. This stage is essential to the future well-being of Boston Terriers. Some steps taken by the owner during this period determine the anxiety levels of fully grown Boston Terriers.

Socialization in early puppyhood is essential, as this is when dogs learn to cope with different life situations. They learn that people and other dogs aren’t threats. 

Boston Terrier puppies who are socialized correctly and early learn to rely on their strengths and their ability to perform.

This table illustrates the main periods of the Boston Terriers’ socialization period.

3 – 4 weeaksTheir senses develop and they are more aware of their sorroundings. They also learn that their sleeping area is not the place to pee and defecate.
4 – 6 weeksPuppies learn how to socialize with their siblings and parents. They begin to understand what is allowed and what is not.
6 – 7 weeksBoston Terrier puppies need to interact with humans and other dogs in a positive manner. Some vaccines can be applied.
7 – 8 weeksVaccination period.
8 – 10 weeksAt 8 months of age, puppies should eat only solid food and be completely weaned. Owners can take the puppies home at this point. Boston Terrier puppies can start their potty training, as their coordination and motor skills are defined by now. Their senses are fully developed.
10 – 12 weeksStarts learning basic comands. They get their second round of vaccines.

Physical Developments

Boston Terrier puppies fully develop their hearing and sense of smell in the socialization stage. Their teeth fully grow and their bodies gain more strength. 

At the end of this period, the puppies can stand and perform various physical activities, such as running and playing.

Emotional Developments

During the socialization phase, Boston Terrier puppies learn how to control their instincts. While playing with their siblings, they learn not to bite hard or to restrain from biting completely. 

Puppies learn how to communicate their feelings and begin to understand what other dogs communicate to them.

An essential aspect of Boston Terriers’ emotional development is they start to form bonds with humans. This begins when they are 4 weeks of age. 

At 4 weeks of age, puppies are still too young to be separated from their mums. This is a good time to visit your future puppy and start building an emotional connection.

By the time they are 10 weeks of age, Boston terrier puppies start to experience fear. They get scared of new interactions or objects. Exposing puppies to various experiences for desensitization to occur is crucial.

Growth and Weight Gain

During the socialization stage, Boston Terrier puppies get from 2.53 pounds or 1.15 kilos to 6.61 pounds, or 3 kilos. 

Care Tips for the Socialization Stage  

During the socialization period, try to:

  • Put your puppy in contact with as many dogs and people as you can. 
  • Change your puppy’s environment often and let them cope with various situations. 
  • Take them to the beach, the mountains, friends’ houses, in the city, in the countryside and more. 
  • Be there for your dog when you expose them to various situations so they don’t feel threatened.
  • Introduce your dog to other animals, such as cats, farm animals, and other pets.
  • Leave your puppy alone and make them realize that he is not in danger when you are not around.
  • Use different sounds around your dog to accustom them to make them less reactive.

4. Juvenile Stage

Boston Terriers Juvenile Stage

The Boston Terrier juvenile stage starts when the puppies are three months old and lasts until they are six months. Training your dog during this period is effective because they look up to you. The juvenile stage is the equivalent of teen years for humans.

Physical Developments

Boston Terriers’ adult teeth fully develop during this stage, which is why they will chew a lot. This is also the time when begin to get sexually mature. 

Emotional Developments

At this age, puppies form a strong bond with their owners. They also learn how to follow rules and to be independent. 

Growth and Weight Gain

During this period Boston Terrier puppies grow from 6.61 to 14.3 pounds. 

Care Tips for the Juvenile Stage  

  • Schedule professional training sessions if you don’t have the time to train the puppy yourself. 
  • Get your Boston terrier as many toys and games as you can.
  • Take your puppy for daily walks and engage them in extensive physical activities.

5. Adolescence

Boston Terriers Adolescence

The adolescence period in Boston terriers begins when they are 6 months old and lasts until they are 18 months of age. This is the last developmental stage.

Physical Developments

During adolescence, Boston Terriers reach their sexual maturity. They experience hormonal changes specific to their gender in this stage.

Female Boston Terriers:

  • Are aroused two times a year. 
  • Have heat periods that last around 2 to 3 weeks.
  • Get their periods every 6 months.

Male Boston Terriers:

  • Are sexually active regardless of the period.
  • They reach their fertility peak after 15 months of age.

After adolescence, they reach adulthood. This is the final stage in their lives, until seniorship.

Emotional Developments

At this point in their lives, Boston Terriers begin to exhibit independent behavior. This is when they start having confidence in themselves and in the bonds they form with their family members.

Growth and Weight Gain

When they start adolescence, Boston Terriers weigh around 14 pounds. As they reach 18 months of age, they weigh up to 25 pounds.

Care Tips for the Adolescent Stage 

  • Be consistent with their training, even if they are almost adults.
  • Be firm and don’t let them control you.
  • Let them have their alone time without having to step into their routine.

When Do Boston Terriers Stop Growing?

Boston Terriers stop growing when they are around 10 to 14 months old, depending on the dog. This is influenced by their genetics. The size of their parents determines how big the puppies grow to be.


Boston terriers grow for the first 10 to 14 months of their lives, whereafter they are fully grown. They reach about 15 to 17 inches in height and 10 to 25 pounds in weight. 

Boston terriers have growth stages, similar to humans. During these stages, they experience various emotional and physical changes. This is how they progressively transform into adults. 

During every stage, puppies have different needs and require training. If you are patient and put in the work, your Boston Terrier puppy will grow to be a healthy dog and will not display behavior issues.

About Ioana Moldovan

Ioana is a Misfit Animals staff writer and psychology student interested in animal behavior. She likes to dive deep into the newest scientific studies to find out the latest discoveries in the field.

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