How Big Does a Terrier Get?

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How big does a terrier get? This may be a thought-provoking question when you’re considering adopting or fostering a terrier. To ensure you’re ready to handle a terrier’s full size, I’m listing the weight, height, and length of some terrier breeds, along with tips on how to maintain the ideal size.

How Big Does a Terrier Get?

How big a terrier gets varies on the terrier breed. For instance, small terriers like Yorkshire, Jack Russell, and Cairn won’t go beyond 20 pounds and 15 inches long.

Graphic image of three different kinds of Terriers with a text explaining how big they can get

Medium-sized terriers such as Boston and Rat may grow big at 25 pounds and 25 inches long. Bigger ones like Pitbull, Wheaten, and Staffordshire may range from 30 to 50 pounds, with the height ranging from 14 to 20 inches.

Terrier Full Size

Jack Russell terriers stop body maturity at 12 months old, letting them weigh at 13 to 17 pounds. Yorkies also stop growing after one year, ranging from four to six pounds and five to nine inches tall. Pitbull terriers achieve full size at 12 months, although they can grow up to 55 pounds.

Wheaten terriers can reach their full size of 30 to 50 pounds just within six to eight months. Meanwhile, Boston terriers complete the last stages of adolescence at around 12 to 14 months of age, and this is where they may reach up to 25 pounds.

Cairn terriers reach body maturity after one year. Despite their small stature, Rat terriers can have full-sized frames of 10-25 pounds and 19-25 inches long within 15 to 18 months. Staffordshire Bull terrier may continue to grow up to three years of age, allowing them to grow a maximum of 75 pounds.

Jack Russell Terrier

Jack Russell is a kind of a terrier belonging to the sporting group. Young Jack Russells would start at around six to eight pounds. As they grow old, they may vary in size since they are mostly working and hunting dogs.

A black and white Jack Russell
  • Weight: An adult Jack Russell terrier, whether male or female, typically weighs 13 to 17 pounds.
  • Height: A female Jack Russell normally stands at 13 inches, while male ones are at 14 inches. If measured from the area above the shoulder up to the ground, Jack Russells would have a withers height between 10 to 12 inches.
  • Length: A fully-grown Jack Russell terrier has an overall body length of 18 to 21.5 inches.

Yorkshire Terrier

Yorkshire terriers are small dogs, so they are considerably shorter than the other terrier types. At birth, they may only weigh three to five ounces. As these tiny furballs grow, they may get the heaviest at around six pounds.

A Yorkshire terrier standing on a rock

Rat Terrier

The rat terrier is a small dog with a sturdy build. Originally bred as a farm dog, it has a lightweight body to improve speed in catching farm rats. Depending on the dog’s purpose, a rat terrier may have bigger muscles that contribute to the overall weight.

  • Weight: A female rat terrier has a weight range of four to 10 pounds, whereas male ones can grow around 10 to 25 pounds.
  • Height: Miniature rat terriers can grow approximately 10 to 13 inches in height. Meanwhile, standard rat terriers can reach up to 18 inches.
  • Length: The body of an adult rat terrier is about 19 to 25 inches long.

Boston Terrier

A Boston terrier has a weight range of 10 to 25 pounds, consisting of three weight categories. Males tend to be bulkier and heavier because they have more muscle mass. Additionally, females tend to mature slower physically.

  • Weight: Female Boston terriers have an average weight of nine to 20 pounds. In contrast, males can hit up to 25 pounds.
  • Height: In general, male Boston terriers stand around 15 to 17 inches, whereas females are 7 to 15 inches tall.
  • Length: When they reach adulthood, the bodies of Boston terriers can grow long, around 22 to 24 inches, unless they are mini Boston Terriers.


A newborn pitbull terrier would be lightweight at two to five pounds. Once pitbull terriers reach adulthood, they may weigh 10 times more than that. The standard size varies from medium to large, although they have a stocky, athletic build.

  • Weight: Pitbull terriers can weigh anywhere from 35 to 65 pounds. Males usually range from 55 to 65 pounds, while the weight of female American pitbull terriers plays around 30 to 50 pounds.
  • Height: Females are generally at 17 to 20 inches in height, whereas males can reach up to 21 inches at the withers.
  • Length: The body of a healthy pitbull terrier has an average length of 28 to 31 inches.

Wheaten Terrier

Similar to the rat terrier, a wheaten terrier was initially bred as a farm dog to guard livestock and kill vermin. Its purpose resulted in a moderate size yet agile body. Nowadays, its body structure is ideal for tracking, obedience training, and animal-assisted therapy.

  • Weight: Females typically weigh approximately 30 to 35 pounds, whereas males are heavier at 35 to 50 pounds.
  • Height: A female wheaten terrier is 17 to 18 inches at the shoulder, while the males are slightly taller at 19 inches.
  • Length: The body of a wheaten terrier is about 26 to 28 inches long.

Staffordshire Terrier

While a Staffordshire bull terrier may weigh around 10 to 28 pounds at three to six months, its size in adulthood depends on whether it has mixed genes or not. This dog belongs to the medium-size classification, so several factors may influence how big a Staffordshire bull terrier gets.

Bull Terrier on a grassfield
  • Weight: A female pureblood Staffordshire terrier may weigh anywhere from 22 to 35 pounds, whereas a male can reach 37 pounds. Meanwhile, a Staffy mixed with American bulldog genes can grow around 55 to 75 pounds.
  • Height: In most cases, male Staffordshire bull terrier tops at about 14 to 16 inches, while the females may only reach 15 inches. In contrast, Staffordshire bull terrier/Labrador retriever mix can grow taller at approximately 18 to 24 inches.
  • Length: Staffordshire bull terriers have an overall body length of roughly 22 to 27 inches.

Cairn Terrier

Cairn terriers are small dogs with short-legged bodies. Their legs and body size are good for bolting after foxes and vermin. Their bodies exude strength yet without the bulkiness of other kinds of terriers.

  • Weight: Adult female cairn terriers have a maximum weight of 13 pounds. On the other hand, males are a bit heavier at 14 pounds.
  • Height: This small yet mighty terrier has a standing height of 15 to 17 inches and a withers height of between 11 to 12 inches.
  • Length: On average, fully-grown male and female cairn terriers have a typical body length of 15 inches.

How Does a Terrier Reach Its Full Size?

In general, small to medium terrier breeds would stop growing at around 6 to 12 months old. However, their skeletal system may continue to develop for up to 24 months. This will also determine how tall or big a terrier will become as a fully-grown adult.

  • The bones in a terrier puppy’s legs develop from growth plates. These are thin cartilaginous regions where the body creates new tissue.
  • During puppyhood, the growth plates are flexible. This is why bone growth is a sensitive phase in your terrier’s life, as it may be prone to injuries.
  • As the new tissue ages, hardens, and calcifies, the tissue eventually becomes a bone.
  • When the growth plates stop producing new tissue for calcification, this means your terrier has reached its full size.
  • Even when a terrier reaches full height, like nine inches for a Yorkshire or 15 inches for a cairn terrier, your pet may continue to gain weight. Mature terriers, especially Staffordshire and pitbull, may bulk up with the help of an exercise regimen, proper nutrition, and resistance training.

Since terriers may take up to two years to grow fully, it’s ideal that you prepare adjustable collars, crates, and harnesses. In this way, you won’t have to replace items constantly. The growing days will go by quickly, and in time, you’ll have a full-grown terrier to care for and train.

How Can I Identify if My Terrier Is Overweight or Underweight?

Purebred dogs such as terriers are known for their predictability in size. Depending on the breed, a healthy terrier can grow up to 25 inches tall, 75 pounds, and 28 inches long. However, it’s not enough that you know how much a terrier weighs.

Black Jack Russel

As a responsible fur parent, it’s also essential that you learn how to identify if your pet is overweight or underweight. In this way, you can avoid potential health issues.

  • Do a profile analysis: As a general rule, a terrier’s abdomen should be higher up than the ribcage. From the front legs, you should see that your pet’s underside inclines toward the rear. An overweight terrier would have no incline, while an underweight dog may form a shallow slope.
  • Check the ribs: Command your terrier to stand still, then run your hands over its sides. If you can’t feel the ribs right away, it’s possible that there’s too much fat, and your dog is on the verge of being overweight. Meanwhile, the ribs of an underweight terrier may protrude too much.
  • Feel the spine: Run your hand gently over your terrier’s spine. If you can’t feel the spine, fat may be burying the bones in an overweight dog. When there’s only a thin flesh on top of the individual vertebrae, your terrier may be underweight.

Having regular weigh-ins is an excellent way to monitor your terrier’s size. Cross-check it with the terrier full-size list, so you’ll know if it’s time to change your pet’s lifestyle and eating habits.

How Can I Keep My Terrier at Its Ideal Size?

It’s vital that you keep your terrier within the average size to guarantee optimum health and prolong lifespan. Here are ways to help your Yorkshire terrier maintain the ideal weight of six pounds or for a Staffordshire bull terrier to grow up to 27 inches long.

  • Provide nutritious yet balanced meals: A combination of healthy human food, treats, and dog food can ensure proper nutrition in terriers. The serving would depend on the breed and age. For instance, an adult Staffordshire terrier needs 2.5 cups of dog food per day, whereas a fully-grown Boston terrier would need two cups.
  • Set a feeding schedule: Scheduling meal time will tune your terrier’s stomach to feel hungry only during eating times. When you provide the right amount of food at the appropriate intervals, your pet will maintain its metabolism rate and eat all the food to become full. This also avoids scavenging for food after meals.
  • Plan physical activities: To help your Wheaten or Boston terrier reach optimum growth, your pet also needs to exercise and do other physical activities. A pitbull terrier may achieve its stocky 50-pound weight if you take it out for a walk or run. You can also make obstacle courses or puzzle games.
  • Schedule vet visits: Whether your terrier needs to lose or gain weight, regular vet checkups ensure your pet’s general wellness. Aside from weight-related concerns, physical examinations and lab tests can detect other potential illnesses. A vet can also recommend vitamins, supplements, and meal plans.
  • Bond with them: terriers crave a lot of attention, so make sure to give them hugs, pets, and time for playing. More than that, pay attention to your dog’s body language, as it often conveys what they are feeling. Bonding with your terrier also lets you know when is the best time for playing, eating, and resting.
  • Minimize stress factors: Harsh training, poor living conditions, and even unpredictable social environments can stress a dog. When terriers feel stress and anxiety, they may be unable to fight infections or diseases.
An image of a Rat Terrier on a snowy ground

What Are Size-Related Health Problems in Terriers?

It’s important to know how big a terrier gets because the size of terriers can significantly influence their health. Particularly when your pet is underweight or overweight, it can be a symptom or effect of a disease.

  • Obesity: Obesity is among the most common health problems in terriers because this breed is prone to overeating. For instance, if a bored Boston terrier may get in the habit of overeating, it may grow beyond the average 25 pounds. Some dogs can also do stress eating.
  • Breathing difficulties: terriers are brachycephalic dogs, which means they have shortened snouts. In an obese dog, the fat in the abdomen would push the diaphragm forward, preventing the lungs from expanding properly. Paired with their shortened noses, it may become harder for a terrier to get enough oxygen.
  • Bone problems: If a Wheaten terrier weighs beyond the average 50 pounds, it may suffer from bone problems as the joints carry extra weight. In effect, the cartilage protecting the joints would wear out, causing osteoarthritis.
  • Diabetes: If a cairn terrier weighs more than 14 pounds, it also risks getting diabetes. This occurs when a terrier’s pancreas can’t produce enough insulin required by the body cell to regulate the carbs and sugar your pet consumes.
  • Cachexia: Cachexia is a condition where a terrier loses lean body mass. If your Jack Russell terrier burns up calories more than usual, its body will change the way it uses carbohydrates, fats, and protein. It may also be an effect of chronic kidney disease, congestive heart failure, or cancer.

Related Questions

What Food Should Terriers Avoid Eating?

Terriers should not eat chocolate as this contains toxic methylxanthines, which are stimulants that can stop the metabolic process. While nuts aren’t as harmful as chocolate, they can block the esophagus or tear the windpipe if your pet doesn’t chew properly. They should also not eat garlic, onion, and raisins.

What Is the Temperament of Terriers?

While originally bred for fighting and hunting terriers, domestic terriers can be full of charm, enthusiasm, and intelligence. Some can be fun and active, making them the perfect companion for adventurous people and fitness enthusiasts.

Meanwhile, others are alert, courageous, and more determined.

How Can I Train My Terrier?

It’s best to apply immediate positive reinforcement when training terriers. Give rewards or verbal praise when your terrier responds to commands correctly. Set a starting point, establish a training schedule, and use training equipment such as toys and treats.

How big is my Boston Terrier puppy going to be?


The size of a terrier, including its weight, height, and length, varies depending on the breed. Other factors like diet and exercise can also influence how their bodies grow. It’s crucial to take note of these details so you can monitor if your terrier is a healthy size.