In comparison to their diminutive size, Jack Russell Terriers possess large, bold, and independent personalities that make them outstanding problem solvers. These hardy terriers were originally bred for English fox hunting and are capable of keeping up with considerably larger Foxhounds on the hunt. They are even courageous enough to dig into the ground and pursue a fox out of its den!

Therefore, being a species bred to hunt in tight confines, how large do Jack Russels grow? If you're the fortunate owner of one of these nimble and intelligent terriers, you can use our Jack Russell Terrier growth chart to monitor your puppy's development.

When Do Jack Russell Terriers Stop Growing?

Observing your Jack Russell develop and mature from puppy to adult is the most rewarding experience. If you nurture them properly, provide them nutritious food, and exercise regularly, your Jack will grow up to be a joyful companion for the rest of their lives.

So, at what point do Jack Russells cease to grow? The majority of them attain full size between the ages of six and eight months but will continue to bulk up and fill out until they reach the age of twelve months.

Their development rate, on the other hand, is dependent on their nutrition, health, and heredity. As a result, each dog will develop at a unique rate.

Jack Russell Terrier Growth Pictures

What is the Standard Jack Russell Terrier Size

When fully grown, Jack Russell Terriers stand between 10-15 inches in height at the shoulder and weigh between 13-17 pounds. Due to breeding and the fact that they are a mixed dog breed, Jack Russell Terriers can vary in size and weight.

Jack Russell Terrier Weight Chart

Here is the weight chart of a Jack Russell:

Age	Average Weight (kg)	Average Weight (lb)
3 months	2.8 – 3.6 kg	6.2 – 7.9 lbs
4 months	3.8 – 4.7 kg	8.4 – 10.4 lbs
5 months	4.5 – 5.8 kg	9.9 – 12.8 lbs
6 months	5.1 – 6.4 kg	11.2 – 14.1lbs
7 months	5.6 – 7 kg	12.3 – 15.4 lbs
8 months	5.8 – 7.5 kg	12.8 – 16.5 lbs
9 months	6 – 7.8 kg	13.2 – 17.2 lbs
10 months	6.2 – 8 kg	13.6 – 17.6 lbs
11 months	6.3 – 8.1 kg	13.9 – 17.9 lbs
12 months	6.4 – 8.2 kg	14.1 – 18.1lbs

Jack Russell Terrier Growth Chart – What To Expect
Jack Russell Terrier Weight Chart by Age

 

Jack Russell Terrier Weight  1-2 weeks

This is the neonatal stage, during which the Jack Russell puppies are completely dependent on their mother's milk for sustenance. Their siblings and mother are critical throughout this era in keeping them warm.

At this stage, their senses of sight, hearing, and smell begin to develop, and you will notice them wagging their tail.

Jack Russell Terrier Weight 3-12 weeks

This is the socialization stage, during which puppies must be introduced to both humans and other canines. By the fifth week, the puppy will be enjoying their playing and will have developed a sense of self-awareness.

Their fangs will begin to develop, and they will begin to bark when they gain sight. Puppies should remain with their mother and siblings to develop socialization skills and to learn to bite with restraint.

Jack Russell Terrier Weight 4-6months

A six-month-old Jack Russell Terrier should weigh between 11 and 14 pounds and be close to their full adult height, which is approximately 10 to 12 inches tall. Males are slightly larger than females, so if your puppy is a boy, he may be at the upper end of these ranges or slightly above.

Jack Russell Terrier Weight  10-12 months

At twelve months of age, the average Jack Russell weighs between 14.1 and 18.1 pounds (6.4 and 8.2 kilograms).

Male and female Jack Russells can reach the same height.

You now know that the majority of Jack Russell's growth occurs during the first 12 months of their lives, but they can reach full maturity earlier, so don't be alarmed if their growth stops prematurely.

After the first year, it is still possible for them to gain weight, so don't be alarmed if your Jack Russell is still a little underweight after their first birthday.

What is the Full Grown Jack Russell Terrier Weight?

According to the official American Kennel Club (AKC) Jack Russell Terrier breed standards, a Jack Russell Terrier should weigh between 13 and 17 pounds. Male Jack Russell Terriers should stand approximately 14 inches tall, while female Jack Russell Terriers should stand approximately 13 inches tall.

These dogs' adult bodies should be proportional, athletic, and compact. Due to the breed's medium-density bone structure, they should appear neither unduly hefty nor extremely thin.

How To Weigh Your Jack Russell Terrier Puppy?

If you want to maintain track of your Jack Russell Terrier's weight, you must first learn how to weigh him properly.

To begin, you should be able to weigh your Jack Russell Terrier at home if he is a puppy or if you are just large enough to hold him. This can be accomplished with a standard bathroom scale.

To begin, weigh yourself and record the result. Then, while standing on the scale, pick up your dog and hold him. The difference in weights represents your dog's weight.

If your dog is too huge to carry, you can either invest in a dog scale, which can cost upwards of $100, or contact your veterinarian. The majority of veterinarian offices will enable you to use their scale.

Unless there is a health problem, you can weigh an adult Jack Russell Terrier once every six months. Once a week is sufficient for a puppy to ensure he is growing normally.

What Is A Jack Russell Terrier’s Neck Size?

To determine the neck size of your dog, use a soft and flexible tape measure to determine the neck size of your dog where her collar naturally falls. Then, put two fingers between your dog's neck and the tape measure to ensure that the dog collar fits snugly but comfortably. Jack Russell Terrier's average neck circumference is between 20 and 14 inches.

How Big Do  Jack Russell Terriers Get?

There are three approaches to estimating the mature size of a Jack Russell Terrier:

Age. Because Jack Russell Terriers are typically fully developed by the time they reach the age of 12, it's unlikely they'll grow much (or at all) when they turn one. However, if your puppy has not yet reached their first birthday, they most likely have some growing to do.

Paws. Additionally, you can examine your Jack Russell's puppy paws to determine if they appear big in comparison to their torso and legs. If that is the case, they are most likely still growing. Oversized paws are a characteristic of adolescent puppies that show they are still growing.

Genetics. Finally, if you purchased your Jack Russell Terrier puppy from a breeder, you can contact them for additional information about your dog's expected size. Your breeder should be able to give you a more specific estimate due to their knowledge of your puppy's parents and previous litter sizes.

Factors That Affect Jack Russell Terrier Puppy Growth 

Genetics

Genetics, in general, has little effect on the growth of Jack Russells but does decide whether they are taller or shorter when fully grown. Generally, the weight and height of the puppy's parents will give you an indication of the puppy's size.

If your puppy's parents are smaller in stature, you need not be concerned, and larger parents will result in larger pups.

Diet & Nutrition

However, you can assist your puppy in reaching their optimum growth potential by providing them with balanced food and exercising them on a consistent basis.

Inadequate nutrition for Jack Russells can result in stunted growth and malnutrition. If the food you feed your puppy is deficient in important minerals, vitamins, and fatty acids, you are endangering them and jeopardizing their health.

Not that supplements cannot compensate for a deficiency of nutrients, but foods high in nutrients can help assure a person's health. It is critical to feed your Jack Russell good food while they are young because this is the most critical stage of their growth and development.

Physical Activity & Health

Jack Russells are active dogs who require daily exercise to maintain optimal health. They can grow overweight if they do not exercise, which can result in health problems such as heart disease and hip dysplasia.

Ensure that your puppy receives 30 to 60 minutes of activity per day to maintain strong broad chest bones and muscles.

Genetics of the Jack Russell Terrier and Common Health Issues

As is the case with many dogs, Jack Russells are susceptible to a variety of health concerns, including the following:

Dislocating lens – sometimes called lens luxation, this disorder occurs when the ligaments that keep the lens in place detach from the lens capsule in the eye. Surgery or topical eye drops on an as-needed basis can help address this issue.

Gum disease – occurs when the supporting components of the teeth become inflamed as a result of bacteria, food, and minerals accumulating, resulting in the formation of tartar. Brush your puppy's teeth to prevent this issue.

Breathing difficulties – the presence of parasites such as lungworms can result in pulmonary inflammation and pneumonia. If your puppy's breathing is affected, surgery should be performed to correct the problem.

Skin problems – Allergies to pollen, dust, washing powders, or wheat can cause skin inflammation in Jack Russells.

Pancreatitis — this is a common condition in Jack Russells and refers to pancreas inflammation. This illness is treatable by abstaining from fatty meals and receiving supportive care.

How do I ensure the health of my Jack Russell Terrier?

As new pet parents are surely aware, this breed is quite active, and your Jack Russel puppy will grow up to be just as energetic – in contrast to other breeds that may outgrow their “puppy period.” Jack Russell Terriers, according to the Veterinary Center of America, require daily exercise. Without daily mental and physical stimulation, these dogs get easily bored, frequently resulting in harmful behavioral difficulties.

As is the case with the majority of purebred dogs, Jack Russell Terriers are prone to a variety of genetic health concerns. However, this does not mean they cannot enjoy a long, happy life. Bear in mind that prevention is always preferable to treatment. 

Along with a balanced diet and regular exercise, screening for hereditary illnesses is a critical component of long-term care for our Jack Russell Terriers. The breed is predisposed to ringworms, eye problems, and ichthyosis (a rare condition that causes painful, scaly skin).

Common Questions about Jack Russell Terrier

At What Age Is A Jack Russell Terrier Fully Grown?

The majority of Jack Russells attain full size between 6 and 8 months of age, but will continue to ‘fill out' and bulk up until around 12 months. Because the rate of their growth is determined by their genetics, health, and diet, each dog develops uniquely.

Factors such as malnutrition and health problems can impair a Jack Russell's growth, while genetics dictate their maximum height. To ensure they reach their full potential, you must provide them with the finest possible upbringing. Provide them with nutrient-dense diets and ensure they receive adequate exercise each day.

How Long Are Jack Russell Terriers Pregnant?

Jacks have an average gestation period of 58–63 days. Fertilization often occurs within five days of mating. During the first half of the time, there is no visible sign of pregnancy.

How Many Puppies Do Jack Russell Terriers Have?

Jack Russells can have between five and eight puppies in a litter. It is determined by the size, age, and health status of your Jack Russell. However, you can anticipate an average of six puppies in a Jack Russell Terrier litter.

What Is The Life Expectancy Of Jack Russell Terriers?

In comparison to other breeds, Jack Russell Terriers live longer, which is one of the advantages of owning one. Thus, what is the life expectancy of Jack Russells?

Jack Russell Terriers live an average of 13 to 16 years. They are, however, susceptible to certain health concerns such as vision problems and deafness, which can significantly reduce their lifespan.

Jack Russells require love, exercise, a balanced diet, and socializing to live their best and longest lives. Providing your puppy with the greatest ethical care possible will guarantee that they have a long and happy life with you.

How Much Does It Cost To Own A Jack Russell Terrier?

After adopting my Jack Russell nearly two years ago and going through the same process as you are now, this is what I can tell you about this subject.

The cost of a Jack Russell might vary greatly depending on how you intend to adopt one. Adopting a Jack Russell from a reputable rescue organization will cost approximately $300.00, whereas adopting a purebred Jack Russell from a reputable breeder would cost between $800.00 and $2500.00.

How To Help Your Jack Russell Terrier Lose Weight If He Is Overweight 

As with humans, exercise is critical for your overweight dog's health. Increased movement helps your dog burn off excess energy (and calories consumed). Avoid panic! Exercising your pet does not have to include marathons or lengthy hikes. Regular walks and the opportunity to run and play safely off-leash. 

Even creating a stimulating indoor environment that encourages your dog to exercise on a regular basis can help. Bear in mind that different breeds require varying amounts of exercise, so visit your veterinarian, breeder, or your dog's breed standard for recommendations on recommended activity levels.

Distinguish Begging from Hunger

Begging is not necessarily motivated by a desire for more food; it is also used to gain attention. (And, by rewarding the behavior, you reinforce and encourage it to continue.) If your dog begs, do not automatically assume he is hungry. Trust your instincts and keep track of the date and time of your last meal. 

If your dog is prone to begging and you are prone to succumb to those puppy dog eyes, choose a high-protein meal with a fiber blend to help control your dog's hunger and voluntary food consumption. In this manner, you may feed your dog with the assurance that he will feel fuller and content for a longer period of time.

Restriction on treats and table scraps

Even when our dogs are not begging, many of us provide an excessive amount of treats and table scraps. Dogs are not required to share our food! Consider treats and scraps for your pet in the same way that you would candy for children to help you keep them in check. If you're going to utilize snacks for training, choose low-calorie, low-fat ones and keep the portions small. 

As an alternative, keep in mind that clickers are excellent for reinforcement… and they have no calories! After all, a few extra pounds can make a significant impact in the lives of dogs, which are significantly smaller than humans. (Even the colossal breeds!) Therefore, focus on a balanced diet and resist the temptation to “reward” them with extra.

Customize Your Dog's Diet

Not all weight-loss foods are created equal, which is why it's critical to match your dog's nutrition plan to their unique needs. Choose a brand that caters to your dog's unique needs, whether they be weight control, dietary sensitivities, or illnesses.

Conclusion on Jack Russell Terrier Growth Chart

Thus, while you are aware that Jack Russells require approximately 12 months to develop physically, they are not fully developed until they reach mental maturity. By their behavior, you can tell the difference between a psychologically grown dog and a puppy.

A puppy is extremely exuberant and reckless, whereas an adult dog is still excitable but to a lesser degree and frequently less irresponsible.

If dogs are not properly socialized, they can be hostile toward others. Without proper socialization, training, and exercise, dogs might have life-long difficulties. If pups are raised properly, they will mature much more quickly and develop a greater capacity for kindness.

For any dog to develop into a caring and loving adult, it is critical that they receive as much human and dog interaction as possible. Socialization should begin when they are seven weeks old, and you should expose them to a variety of different experiences.

Frequently Asked Questions: