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How Big Is A Full-Grown Jack Russell Terrier? (Height, Weight & Size)

Ever since the sitcom Frasier, I’ve been wanting to get myself one of those Frasier dogs.

What type of dog is the Frasier dog? A Jack Russell Terrier.

On the show, the dog stays quite small, but before getting my own Jack Russell I wasn’t sure what to expect in terms how the size of an adult Jack Russell Terrier.

On average, a full-grown Jack Russell Terrier weighs between 13 pounds and 17 pounds with a height of 10-inches to 15-inches at the shoulders.

If you’re also considering getting a Jack Russell, then let me share what I’ve learned with my own doggo and how the size of an adult Jack Russell can vary.

Below we’ll look at how the size of a Jack Russell varies between male and female dogs, as well as how a Jack Russell mix changes things, plus other factors that determine how big (or how small) your Jack Russell grows to be as an adult dog.

How Big Do Male And Female Jack Russells Get?

As you might expect, Jack Russells tend to stay relatively small, even as a full grown adult dog.

At what age is a Jack Russell generally considered to be a full grown adult dog? Between the ages of 6-months to 8-months.

Use the chart below to get an idea of the height and weight for this breed’s male and female dogs.

HeightWeight
Adult Male Jack Russell10-in to 15-in12-lbs to 17-lbs
Adult Female Jack Russell10-in to 15-in12-lbs to 17-lbs

How Heavy Will A Jack Russell Get?

If you’re looking for a purse puppy or a dog that you can carry around, then you may want to know how much your little Jack Russell pup will weigh once he’s full grown.

On average, a full grown Jack Russell Terrier weighs between 12 pounds and 17 pounds.

How Heavy Is A Jack Russell Terrier Puppy?

Now that you know how much an adult Jack Russell Terrier weighs, you may want to know how that compares to a puppy of the same breed.

  • At 3 months old, a Jack Russell Terrier puppy weighs an average of 7 pounds.
  • At 6 months old, a Jack Russell Terrier puppy weighs an average of 10 pounds.

As you can see, some full grown adult Jack Russells don’t weight much more than a 6-month old puppy.

man feeding jack russell puppy

Size Differences by Terrier Breed

To give you an idea of how the weight and height of a full-grown Jack Russell Terrier varies, below we’ve done a comparison with other terrier breeds.

HeightWeight
Russell Terrier8-in to 12-in11-lbs to 16-lbs
Parson Russell Terrier12-in to 14-in13-lbs to 17-lbs
Jack Russell Terrier10-in to 15-in12-lbs to 17-lbs

Mixed Jack Russell Terriers Size Guide By Breed Mix

If you don’t have a pure bred Jack Russell, then that breed mix will often result in a different size dog than the values you see above.


Jack Russell Terrier Breed Mix
Height (inches)Weight (lbs)
Bo-Jack (half Boston Terrier)10 to 15 inches10 to 16 lbs
Border Jack (half Border Collie)16 to 22 inches22 to 32 lbs
Co Jack (half Corgi)10 to 13 inches18 to 28 lbs
Cocker Jack (half Cocker Spaniel)13 to 20 inches15 to 30 lbs
French Bull Jack (half French Bulldog)11 to 14 inches13 to 28 lbs
Golden Jack (half Golden Retriever)10 to 15 inches13 to 19 lbs
Husky Jack (half Siberian Husky)17 to 19 inches30 to 40 lbs
Jack Chi (half Chihuahua)12 to 15 inches8 to 18 lbs
Jack Russell (half German Shepherd)13 to 14 inches14 to 20 lbs
Jack-A-Bee (half Beagle)10 to 16 inches15 to 35 lbs
Jack-A-Poo (half Poodle)10 to 16 inches13 to 25 lbs
Jack-A-Ranian (half Pomeranian)12 to 15 inches6 to 14 lbs
Jackshund (half Dachshund)8 to 23 inches15 to 28 lbs
Jarcairn (half Cairn Terrier)11 to 12 inches11 to 12 lbs
Jug (half Pug)10 to 15 inches8 to 13 lbs
Papijack (half Papillion)10 to 15 inches8 to 15 lbs
Rustrailian Terrier (half Australian Terrier)10 to 18 inches10 to 25 lbs
Yorkie Jack (half Yorkshire Terrier)10 to 12 inches6 to 12 lbs

As you can see, there is a lot of variety when it comes to a mixed breed Jack Russell.

Factors That Affect Growth And Size Of A Jack Russell Terrier

Assuming that you have a pure bred Jack Russell, there are still other things that impact the size of your dog in addition to the breed or mixed breed.

Let’s go through the things that play a part in determining how big, or how small, your Jack Russell grows up to be.

Genetics

The best indicator of how big your Jack Russell puppy will grow to be as an adult is the size of the dog’s parents.

If you can, it is a good idea to visit the breeder or the person who gave you your Jack Russell and see if you can look at the dogs who made your little doggo.

Seeing the size of the parent dogs is really the best way to know what to expect from your little Jack Russell.

Diet

The saying ‘you are what you eat’ applies to dog as well as humans.

And if you’re not giving your dog the proper nutrients, then he won’t grow like he should.

What does this mean for your Jack Russell?

If you don’t give your dog food with proper nutrients, then he will turn out smaller than your average Jack Russell since the dog won’t be as healthy as he should be with the proper diet.

It could even cause other health issues that affect the dog’s growth.

So, make sure you’re feeding your dog the right stuff and only quality dog food.

RELATED: What’s The Best Dog Food For Small Dogs?

jack russell terrier eating

Fitness

If you don’t give your Jack Russell regular exercise, then he could turn into a little fatty that weighs a lot more than the average for the breed.

It’s not healthy for your dog to turn into a little butterball, so don’t let him get overweight.

Exercise your Jack Russell daily to keep the dog healthy and happy.

Is A Jack Russell Terrier Considered A Small Dog? Or Medium Sized Dog?

Within the dog community there is some chatter in regards to how small does a dog have to be for it to be considered a small dog versus a medium dog.

I think the reason that this discussion happens with Jack Russell Terriers that there are plenty of dogs small than a Jack Russell.

However, a Jack Russell Terrier is a small dog, not a medium dog.

Can you find smaller dogs? Yes, but a Jack Russell is still a small dog.

Final Word

As you can see, a Jack Russell Terrier doesn’t get all that big when it is full grown.

However, if you have a mixed breed Jack Russell, then there is a chance that it will grow to be a larger adult dog.

Use our charts above to get an idea of how big your Jack Russell puppy will grow to be as an adult.

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