Jack Russell Terrier Growth & Weight Chart: Everything You Need to Know

by Aliyah Diamond
Pawlicy Advisor
Pet Care Blog
Jack Russell Terrier Growth & Weight Chart: Everything You Need to Know
Track your puppy's growth and development using our Jack Russell Terrier growth chart. These estimates allow you to compare their actual weight to the ideal range per age in weeks, but talk to your vet if you have any concerns.

In contrast to their small size, Jack Russell Terriers have big, bold, and independent personalities that make them excellent problem solvers. These tough terriers were initially bred for English fox hunting and can easily keep up with the much larger Foxhounds during the hunt. They are even fearless enough to dig into the ground and chase a fox from their lair!

So, as a breed designed to hunt in small spaces, just how big do Jack Russels get? If you’re the lucky pet parent to one of these quick and clever terriers, you can use our Jack Russel growth chart to track your puppy’s development.

Here’s everything you need to know about Jack Russell Terrier weight, size, and growth rate:

Pro Tip: New pet parents can get reimbursed for up to 90% of veterinary bills by enrolling in a pet insurance plan. Compare options for Jack Russell health insurance to get peace of mind knowing your pup has access to gold-standard care for life.

Jack Russell Terrier Growth & Weight Chart

Age Weight
1 month old 2 - 4 lb
2 months old 4 - 6 lb
3 months old 6 - 8 lb
4 months old 7 - 10 lb
5 months old 8 - 11 lb
6 months old 11 - 14 lb
7 months old 11 - 14 lb
8 months old 12 - 15 lb
9 months old 12 - 16 lb
10 months old 13 - 17 lb
11 months old 13 - 17 lb
12 months old 13 - 17 lb
2 years old 13 - 17 lb

Jack Russell Terriers are small dogs with an athletic, balanced, and alert appearance. Please keep in mind that the following Jack Russell Terrier weight numbers are estimates, and your Jack Russell Terrier’s growth rate may be different. Like humans, puppies grow at different rates, and this is entirely normal.

Your Jack Russell Terrier’s health is the most important thing. If your puppy is way behind or ahead of the following weight estimates, please consult with your veterinarian about your Jack Russell Terrier’s growth and health.

At what age is a Jack Russell Terrier fully grown?

Most Jack Russell Terriers stop growing around one year old. If you take a look at our Jack Russel weight chart, you can see that breed’s growth tapers off at the 12-month mark. However, that’s not to say your JR at home won’t get any bigger! If your puppy continues to gain significant weight after their first birthday, consult with your veterinarian as they may be putting on excess pounds that can lead to secondary health problems in dogs.

How big should a 6-month-old Jack Russell Terrier be?

A 6-month-old Jack Russell Terrier should weigh around 11 to 14 pounds and will be close to their full adult height, putting them about 10 to 12 inches tall at six months of age. Males tend to be slightly larger, so if your puppy is a boy, he might be on the higher end of these ranges or a little above them.

Two Jack Russell Terriers play with frisbee

Pro Tip: Download a new puppy checklist with information detailing how to set up a vaccination schedule, wellness plan, and microchips, along with helpful advice on keeping your puppy safe and healthy.

How much bigger will my Jack Russell Terrier get?

There are three ways to predict the size of a Jack Russell Terrier at maturity:

  1. Age. Jack Russell Terriers are usually full-grown at 12 months old, so it’s unlikely they’ll grow very much (or at all) after they turn one. But If your pup hasn’t celebrated their first birthday yet, they probably still have some growing to do.
  2. Paws. You can also take a look at your Jack Russell’s puppy paws to see if they look oversized next to their body and legs. If so, then they’re probably still growing. Oversized paws are a classic adolescent puppy feature that indicates they are still filling out.
  3. Genetics. Lastly, if you bought your puppy from a Jack Russell Terrier breeder, you can contact them for more information on your pup’s predicted size. Your breeder should be able to provide you with a more precise estimate since they have additional information on your puppy’s parents and past litter sizes.

What is the size of a full-grown Jack Russell Terrier?

A Jack Russell Terrier should weigh between 13 and 17 pounds, according to the official American Kennel Club (AKC) Jack Russell Terrier breed standards. A male Jack Russell Terrier’s ideal height is about 14 inches tall, while a female Jack Russell Terrier should be slightly shorter at 13 inches tall.

As adults, these dogs should have proportionate, athletic, and compact bodies. The breed is of a medium-density bone structure, so they should not appear overly heavy nor excessively thin.

Jack Russell Terrier waits for owner to toss ball

How do I make sure my Jack Russell Terrier is healthy?

As new pet parents probably know by now, this breed is highly active and your Jack Russel puppy will grow up to be just as energetic - unlike other breeds that might grow out of their “puppy stage”. According to the Veterinary Center of America, Jack Russell Terriers need ample exercise every day. Without daily mental and physical stimulation, these dogs can quickly become bored, often leading to destructive behavioral issues.

Like most purebred dogs, Jack Russell Terriers are susceptible to a variety of genetic health problems, but that’s not to say they can’t live a long, happy life. Remember: prevention is always better than treatment. Along with a healthy diet and exercise, screening for genetic diseases is an essential part of caring for our Jack Russell Terriers in both the short and long term. The breed is especially prone to getting ringworms, eye disorders, and ichthyosis (a rare condition that causes painful, scaly skin).

Jack Russell Terrier Veterinary Costs

Ichthyosis is an incurable, chronic skin condition that requires medicated shampoos and rinses to manage. Similarly, ringworms are typically treated with prescription drugs including topical and oral medications. The ongoing cost of treatment for Jack Russell hereditary conditions can quickly add up over the course of your dog’s lifetime.

Pet insurance acts as a safety net should unexpected health conditions arise by reimbursing you for up to 90% of out-of-pocket veterinary costs. As pets continue to live longer, they require more veterinary care so they can have the best quality of life. Compare pet insurance plans with Pawlicy Advisor to find the right solution customized to your needs.

Key Takeaways

  • Our Jack Russell Terrier growth chart predicts the weight of your puppy until they stop growing around age one.
  • Official AKC standards say that Jack Russels should weigh between 13 and 17 pounds in adulthood, and males will be a little heavier than females.
  • As a breed, Jack Russell Terriers are prone to a number of hereditary conditions.
  • The best way to ensure your JR pup lives a happy, healthy life is with preventive care and routine vet visits - so you may want to enroll in a pet insurance plan to save money on covered costs.

Aliyah Diamond

About the author

Aliyah Diamond

DVM Candidate - Cornell University College of Veterinary Medicine

Aliyah Diamond has more than ten years of experience in animal hospitals - working with dozens of species from dogs and cats, to elephants and snow leopards. Her lifelong passion for helping animals currently has her earning her doctorate of veterinary medicine at Cornell University and helping Pawlicy Advisor educate pet parents.

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