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How Big Do Rex Rabbits Get? [Average Size Guide For Owners]

If you’re looking at getting a rabbit; you’ll soon come to realise that there are many different breeds to choose from. Rex rabbits are a popular choice, but what kind of size do they generally reach? And what can this mean when it comes to space and housing them? Here is what the research has shown.

So, how big do Rex rabbits get? There are two size varieties of Rex Rabbit; the standard and the mini. Standard Rex rabbits typically weigh between 7.5 to 10.5 pounds, reaching their full adult size by eight or nine months of age. Mini Rex rabbits weigh between 3 to 4.25 pounds, but grow quicker – reaching their full size at around six to seven months of age.

Rex rabbits are a popular breed, partly because they suit so many different living situations!

They can live happily in apartments, larger houses, be housed indoors, and outdoors; with a single person, or in families with children.

Generally, these bunnies have a calm and docile temperament; they are also affectionate, playful, and intelligent.

They are generally content with frequent handling and petting, even from an unfamiliar person.

Although, especially so with their owners whom they can become quite attached to.

Of course, this is all assuming the handler is gentle, and the rabbit is routinely allowed out of the cage and down on the floor. Able to explore their surroundings.

Nevertheless, this is fantastic news if you are seriously considering the breed.

Besides, with two varieties of Rex rabbits to choose from, and the ability to get a larger or smaller bunny to suit your needs and preferences – what more can you ask for!

Let us now take a closer look at the size of the Rex breed, along with their typical growth trajectory and the amount of space you need to allow them for optimal health and wellness!

What Size Are Rex Rabbits?

Rex rabbits come in two different sizes, known as the standard and the mini:

  • The standard Rex rabbit typically weighs between 7.5 to 10.5 pounds and generally reaches 12″ in length.
  • A mini Rex rabbit will weigh between 3 to 4.25 pounds and generally reaches 10″ in length.

Interestingly, females are known to grow slightly larger and weigh a few more pounds than the males.

But of course, there will always be individual variance.

This is because rabbits, even within the same breed, are genetically predetermined to reach a certain size.

This is why some will always be larger than others.

And its a trend that will only continue.

Bunnies, large or small for their breed, will pass their size genes on to their young. Whom in turn will do so again, if they were to breed.

It is then when two large bunnies of the gene pool procreate, you get the giants of the breed who hover at the top of the size expectations.

One thing to consider here however, is that the two varieties should not generally be bred together.

Otherwise, the distinction between the two breeds can be quickly blurred.

But beyond just genetics there are other factors involved which impact size

How an owner cares for their rabbit will have a big impact on whether they can reach their full-size potential.

As such, if you don’t look after your rabbit properly, then they can experience stunted growth.

The same can be said for any injuries, particularly where growth platelets are concerned.

It is especially important to feed a young rabbit a good diet; nutritionally balanced pellets along with high-quality alfalfa hay to promote optimal growth.

Housing is another important consideration in regard to size.

Most pet rabbits can be safely kept in cages in the home; so long as there is enough space to let them run freely.

They need to be suitable, of course.

Unfortunately, many cages that are sold for rabbits are often too small and this can have a dramatic effect on the general health, wellbeing and sometimes even their size.

Bigger is always better when it comes to an enclosure for rabbits; so it’s important that they are responsibly housed.

Generally speaking, cages should be at minimum four times the size of a rabbit – and of the specific breed.

At What Age Is A Rex Rabbit Considered Fully Grown?

Rex Rabbits are considered fully grown between the ages of 6-9 months. With less growth required, Rex Rabbits typically grow quicker than the standard breed variety:

  • Standard Rex rabbits are fully grown by the time they are between eight and nine months old,
  • Mini Rex rabbits are fully grown between six to seven months old.

And its not just the size differs.

The lifespan of a standard Rex rabbit is between five and six years, whereas a Mini Rex rabbit, normally lives a little longer, typically between seven to nine years.

In fact, it helps if you think of it this way: one year of a rabbit’s life roughly equates to ten human years.

And the lifespan of a rabbit has an impact over their development and behavior too.

Importance Of Diet For Growth

Providing your rabbit with high quality, balanced and a nutrient-dense diet will help them to grow healthy and reach their full-size potential.

Rex rabbits are like any rabbit in terms of nutrition; their diet must consist of at least 70% hay which must be fresh and of high quality.

Orchard hay is a good option here.

From there, the other main staple of the diet should come in the form of pellets.

Lastly, the remainder of the diet can include a varied mix of fruits, vegetables, and leafy greens.

Fruit and veg should only be offered sparingly, and as a treat, to a Rex rabbit.

While there are vitamins and minerals on offer, some are known to contain high levels of carbohdrate, sometimes in the form of sugar.

So, it’s important that you do your research on any potential food source. Especially if it is new to them and you have not fed it before.

Always err on the side of caution and check all foods for their safety and appropriate serving sizes.

Some foods, even those less obvious, can make them sick.

It’s essential to know what these are.

Rabbits, like most creatures, need plenty of water too.

This will ensure they are adequately hydrated which again is essential for good health.

Rex Rabbit Development Stages

Let us now take a closer look at the different developmental stages of a Rex Rabbit, and what you can expect in terms of behavior throughout each one.

Reaching Sexual Maturity

Before male rabbits reach their full and final adult size, they reach sexual maturity.

This is when they can procreate, and have babies if they were to engage in such activity.

Sexual maturity for males begins at three or four months of age; whereas it’s around five to six months for females.

And this life-stage is marked by some behavioral changes.

Both males and females can display aggressive behavior at this time – where males have been known to spray urine, or an attempt to mount your feet.

Females will become territorial and it has even been known for them to experience phantom pregnancies!

Most owners will choose to neuter or spay their rabbits to prevent these kind of problematic behaviors.

Adolescent Stage

By the time Rex Rabbits are between 6-9 months old, they are considered adolescents.

This is the stage that rabbits typically fully mature, fill out and reach their expected final size.

If a rabbit is neutered, they are more likely to gain weight and exercise less during this period.

You may even need to exercise portion control with their pet rabbit, limiting their food to around an eggcup per day to prevent too much weight gain.

But, just something to consider here!

Its also when hereditary dental problems can start to develop and where you may begin to notice.

This is why setting good habits from an early age is critical and making sure your pet Rex’s diet is rich in good quality grass or hay.

Active Stage

When your Rex is between one to three years of age, they are likely to become more active.

Your pet will need plenty of exercise, but must do so in a safe and secure environment!

At this stage, there will be lots of chewing, digging, and exploring.

This can be a challenging time for many owners especially since they will need lots of attention from you.

Signs of Aging

Between the ages of three and five, is when most rabbits begin to sleep more and become less active.

You are likely to experience more affection from your bunny as they would much rather curl up with you than run around.

By this stage they will be very familiar with you and will have a lot of confidence in your care.

As such, this can be a lovely and somewhat peaceful time and period of ownership.

How Much Space Do Rex Rabbits Need?

Rex Rabbits require an enclosure that has at least 12 feet of space. They also require a further 32 square feet of open play space that you can let them out to exercise, which should be fenced by a pen or a gate.

Adequate housing is in many ways essential. It should be constructed from high quality materials, and give them sufficient space to eat, play and eliminate.

Overly cramped housing is one of the most common and unfortunate mistakes of new owners; and its far from ideal for your pet.

In terms of the cage specifics, ensure that is made from a durable wire yet also has a solid bottom.

A wire bottom is a no-no; it can cause injury to your rabbit as they can easily get their feet/legs trapped.

Routinely letting your Rex rabbit out of the cage is important too.

The more often you can do so the better for their wellbeing and welfare. So long as they are monitored and can exercise in a safe area, of course.

Letting your rabbit out of their cage will help them to become socialized, plus you can use this as an opportunity to interact with them.

But you do need to be careful.

Rabbits tend to chew on everything they come across, and they have strong teeth. If you do not keep a mindful eye over them, or carefully control their roaming space – the results can be catastrophic.

Aside from your clothes and furniture, there is always a danger to your rabbit from chewing on electric wires, cable or other electrical items.

It can be fatal.

So, it’s imperative to rabbit-proof your home; this involves ensuring the entire area is safe before getting your rabbit out.

This is perhaps the main reason why owners often get pens for their rabbits; like this best seller on Amazon.

It just allows for much better and less stressful roaming!

And, you can always set it up in the garden or yard too!

Rex rabbits as a breed are known to enjoy play and stimulation, so it also helps to provide them with plenty of toys to chew and keep them entertained.

Simple objects like a toilet paper roll will work well, along with more sophisticated toys you can get from your local pet store, or more easily online from Amazon.

Never the less, toys provide enrichment, which rabbits need much of, in addition to space.

Thankfully, despite their specific cage and space requirements, Rex rabbits can live happily in most living situations.

They are quite easily accommodated, and their cage should still fit in a small apartment, although a larger house, with its own separate room, is ideal if you can.


Rex rabbits are not very large. The standard Rex is considered to be medium-sized, whereas the mini is classified as small (believe it or not!)

Either way, these rabbits are known for being easy to accommodate and live with.

In fact, its quite the pleasure.

Aside from having a gentle temperament, they are intelligent and easy to train; doing well with treats and even responding to their name if treats are involved.

These bunnies enjoy jumping and running about, but they are equally like to be docile and show their affection.

So, if you are looking for a rabbit breed for children – these would make an ideal choice.

But just keep in mind that your Rex Rabbits should be mostly kept indoors. In fact, they generally do not do well with weather extremes and do best with indoor living.

So consider the space you can afford, and what this will mean for your particular living situation ahead of time.

Generally speaking, the Rex Rabbit is an excellent breed; they are typically healthy and easy to take care of. And are rewarding.

It doesn’t take long for a new owner to fall in love with their personality, and due to their size and willingness, are just great to cuddle!

Are you still researching for a rabbit breed? Wondering what their respective sizes are? My following guide will be of help: