How Big Does A Guinea Pig Get? All You Need To Know

Are you planning on bringing home a guinea pig but are worried about How big does a guinea pig gets? Well, it is only fair to be wondering about it. In fact, in all fairness, before one brings home a guinea pig, knowing about all the possible intricacies is the best approach. As a proud pet parent of two guinea pigs, I think I can answer the question – How Big Does A Guniea Pig get, and various other inquiries related to a guinea pig.

How Big Can a Guinea Pig Get?

There are various breeds of guinea pigs used as pets today, just like hamsters, dogs, cats, and other common household pets. There are 13 guinea pig breeds recognized by the American Cavy Breeders Association (ACBA). However, there are many more.

how big does a guinea pig get

Some breeds are fairly huge, while others are much smaller. As a result, the species of guinea pig has a considerable impact on its weight and length.

Unlike other rodents, most guinea pigs do not have a visible tail that may be used to calculate their overall size. This is a good thing because it can be misleading when the tail represents half of a rodent’s whole length!

The tails of guinea pigs with visible tails are generally just 1 to 1.5 inches long (2.5-3.8 cm). The guinea pig’s luxurious fur coat hides them most of the time.

The typical size of a guinea pig is between 8 and 10 inches (20-30 cm).

Let’s look at some exceptions now that we know how large the average guinea pig is.

The Largest Guinea Pig Breed

The Rex guinea pig wins the title of largest guinea pig breed, reaching a mature size of 17 inches (43 cm)! No other modern guinea pig breed comes close to the enormous mature length of the Rex guinea pig!

On the other hand, this one is a gentle “giant,” as it’s also known as a low-maintenance lap pig who enjoys attention.

Guinea Pig Breeds of a Large Size

If you’re wondering how big does a guinea pig gets, you’ll be interested to learn that the larger guinea pig breeds grow to be around 4 inches long. Each breed’s bigger pigs are 10 to 12 inches tall (25-30 cm).

The following are some of the most popular giant guinea pig breeds:

  • Abyssinian: up to 12 inches (20 cm)
  • Cornet: up to 12 inches (20 cm)
  • Lunkarya: up to 12 inches (20 cm).
  • Texel: up to 12 inches (20 cm)
  • Peruvian: up to 12 inches (20 cm)
  • Himalayan: up to 12 inches (20 cm)
  • Teddy: up to 12 inches (20 cm)
  • Sheba: up to 12 inches (20 cm)
  • Ridgeback: up to 12 inches (20 cm)

The Abyssinian Guinea Pig Size

This breed of guinea pig, Abyssinian, is one of the most popular and distinctive pet guinea pig breeds. Cowlicks (“rosettes”) form swirls of fur all over these lovely piggies’ bodies, giving them a magnificent coat.

Their fur also has beautiful color bands that vary from pristine white to deep grey. Gender, birth order, litter size, food, and overall health all influence the size of an Abyssinian full-size guinea pig, which can range from 8 to 12 inches (20-30 cm).

The United States Guinea Pig Size

On the guinea pig size chart, the American guinea pig is one of the smaller breeds. Adult American guinea pigs are on the lesser end of the range in terms of length, reaching just 8 to 9 inches (20-22 cm) at maturity.

Fact About Guinea Pigs

Guinea Pig, Few, Hagenbeck, Hamburg

Here are some lesser-known facts about this mysterious and lovely animal.

They have an unusually high number of toes.

Guinea pigs’ front feet have four toes, while their rear foot only has three. While this is advantageous for tunneling and digging, it also means they are not particularly nimble and are only capable of climbing low-pitched ramps.

They are, however, quite curious, so ensure sure their habitat is free of risks that might enable curious cavies to damage themselves.

They aren’t fond of bunnies.

It’s a common misconception that you can raise guinea pigs and rabbits together amicably. Rabbits will not only bully guinea pigs, but they also have quite diverse demands. Rabbits can potentially spread infections that are dangerous to guinea pigs.

Guinea Pigs only sleep for a few hours at a time.

Guinea pigs are crepuscular creatures, meaning they are most active around dusk and morning, but these fur babies can be awake for up to 20 hours a day.

This means they’ll need continual access to food, water, partner guinea pigs, secure hiding spots, and toys to keep your furry friend entertained, as well as an exercise area with tubes to tunnel through, shelters to hide in, and deep hay foraging and nibbling areas.

They like conversing with one another.

These furry little animals need to be around other guinea pigs and should always be maintained in pairs or small groups, despite adoring human attention.

They use a variety of noises to communicate, including the well-known ‘wheek-wheek’ call – a sign of eagerness or to locate a companion – and a quiet ‘purring’ sound that they make when they are comfortable and relaxed.

When they are exploring, they also make a succession of quick ‘putt-putt’ noises.

They’re not from Guinea.

Guinea pigs are natively from the Andes Mountains in South America. It’s unclear what the guinea in their name means.

One hypothesis is that they were carried to Europe by Spanish explorers in the 1500s via Guinea in Africa, leading people to believe they originated there or that the name is a misspelling of ‘Guiana,’ a South American region.

They have nothing to do with pigs.

Guinea pigs are rodents, despite the fact that males are called boars and females are called sows. Because of their scientific name, ‘Cavia porcellus,’ they are sometimes known as ‘cavies.’

Porcellus is a Latin word that means “small pig.” The pig-like squeaking noises they produce may have given them this moniker.

They leave a fragrance trace on their belongings.

Guinea pigs scent mark objects by rubbing their chins or cheeks against them, which helps to maintain their environment feeling familiar and pleasant.

This is why, after cleaning, be sure to return part of the old bedding to their lodging. They also drag their butts on the ground to leave fragrance signals that only other guinea pigs can understand.

What factors affect the Size of Guinea Pigs?

Gender is the most evident factor. Males, regardless of breed, are often larger than females. Males will develop quicker than females, but both genders will cease growing at around the same time.

Another consideration is the breed. Some breeds are significantly larger than other guinea pig breeds. The Hartley guinea pig is one of the most popular, particularly among scientists.

As a result, we have the most scientific data on their pace of growth. Other breeds, on the other hand, will mature at various speeds and attain different sizes.

Diet has an impact on body size. However, if properly nourished, all guinea pigs should be able to keep up with their gender and species peers.

At What Age Is A Guinea Pig Considered Fully Grown?

A guinea pig is not considered an adult until it is six months old, but this does not mean that it is completely matured.

Guinea Pig, Rodent, Cute, Eyes, Fur

Most of these furry little animals will continue to grow until they are around 14 months old, and as they get closer to that age, their growth rate slows until they no longer increase significantly.

Estimating their age might be tricky if you haven’t had a guinea pig since they were a baby. In the absence of any other information, size can be a reliable indicator of age. 

You may be able to establish a reasonable estimate of your guinea pig’s age using certain standard parameters, although this is simpler to accomplish when the cavy is still young.

As previously said, growth slows at full maturity. Hence other markers like general health and condition may be a better measure of age.

Guinea Pigs Keep Growing Till What Age?

Guinea pigs retain the same size for most of their adult lives until they achieve full maturity at 14 months of age. They can develop a little bit more past this point, but not much.

Guinea Pig, Happy Birthday, Animal

Guinea pigs, on the other hand, will develop fast up to this time while still young. It’s helpful to have an approximate concept of how much a guinea pig will weigh at various growth phases so you can make sure they’re healthy and on track as they grow.

  • Following that, the rate of increase will begin to decelerate. The puppy will be around 8-10 inches long and weigh 0.8-1.1 pounds by the time it is 16 weeks old.
  • Puppies, or baby guinea pigs, are between 0.15-0.25 pounds and are about 3-4 inches long at birth — a quarter of their full size! A sow will usually have three puppies, but litters might have up to six; bigger litters will frequently have smaller offspring.
  • From here, the puppies will develop swiftly, doubling in size in the first eight weeks of life. At this point, the average guinea pig will weigh 0.4-0.55 pounds and measure 6-8 inches in length.

Most of these furry animals will be almost the same length as their eventual adult size at this stage, but they will continue to gain weight until they are fully grown. Between the ages of 16 weeks and 14 months, a guinea pig’s weight can easily double.

Do Guinea Pigs Come in Varied Sizes?

Guinea Pig, Animal, Rodent, Smooth Hair

Due to various factors such as heredity, diet, and physical activity, there will always be some difference in size between guinea pigs of the same breed.

And some of the variances between individuals will be attributable to general body composition – some cavies will be bigger than others, even obese.

When comparing individuals of various breeds, however, the highest size difference amongst guinea pigs occurs.

The American Cavy Breeders Association (ACBA) has identified 13 different guinea pig breeds. A few others aren’t yet recognized; all of these guinea pig varieties come in a wide range of sizes.

Some guinea pig breeds are substantially bigger than the usual, such as the Rex guinea pig, which may reach a mature size of 17 inches. Other breeds, such as the Texel and the American guinea pig, are often slightly smaller than the norm.

As you can see, the cavy’s breed significantly influences the eventual size at maturity.

How Big Can a Male Guinea Pig Get?

Males must appear to be somewhat larger than females, and this is exactly the situation with guinea pigs. Male guinea pigs (boars) are not only taller but also heavier. If you have a boy, this means that the fluffy ball may reach the breed’s maximum length.

For example, American guinea pigs are usually between 8 and 9 inches long. Thus a male cavy will most likely be approximately 9 inches long.

How Big Can a Female Guinea Pig Get?

Female guinea pigs (sows) are often smaller than male guinea pigs (boars). This detailed information can also be used to determine if the cavy is male or female (after the fluffy balls reach the age of 3 weeks).

Sows are not only smaller than male guinea pigs, but they are also lighter. The bulk of the females will be 8 to 10 inches (20- 25 cm) tall.

How Big Does A Guinea Pig Get?

A fully grown guinea pig may vary in size based on gender and breed. Guinea pigs typically range in length from 10 to 12 inches (25.4 to 30.5cm) and weigh between 1.5 and 2.6 pounds (700 – 1179 grams).

Guinea Pig, House Guinea Pigs

If you’re having trouble telling the difference between a male and a female guinea pig based on their weight or size, consider separating them based on their genital area.

To put it in perspective, dwarf hamsters grow to be around 2-4 inches (5.5-10.5cm) long, which is more or less the same size as a young guinea pig.

Measure your Guinea Pig

To measure your guinea pigs, set up a tape measure and try to align your guinea pig with it. The measurement should be made from the guinea pig’s tip to its tail!

Is The Size of the Guinea Pig Dependent on the Breed?

Their breed determines the size of many animals. Dogs, for example, may be as large as a horse or as little as a guinea pig, but does the size of a cavies body rely on the breed or not?

The fact is that guinea pig breeds do not come in a wide range of sizes. Almost all cavies may reach a maximum size of 30 cm (12 inches) in length. There is, however, a guinea pig breed that can grow to be a little bigger!

Guinea Pig, Smooth Hair, Silver Agouti

The Rex guinea pig may reach a height of 17 inches (43 cm)! Despite his moniker, the individual does not resemble a dinosaur. It resembles a Teddy guinea pig but is somewhat larger and has a dense wavy coat.

The Rex guinea pig is a true behemoth among guinea pig breeds. However, having your own Rex does not guarantee that it will be exactly 17 inches long. Other cavy breeds, such as the Abyssinian guinea pig, are typically between 8 and 12 inches long (20-30 cm).

The American guinea pig is another popular breed. This type is a little smaller, measuring between 8 and 9 inches in length (20-22.86 cm). Remember that the length of a cavy is determined by heredity, diet, overall health, and even the animal’s sex.

What is the size of a Baby Guinea Pigs?

If you think adult guinea pigs are adorable, wait till you see them as infants! Because baby guinea pigs don’t stay babies for long, only breeders get to witness these little copies of the pets we all adore.

Newborn Guinea Pigs

If you’re wondering how large baby guinea pigs are, they can be as little as 3 to 4 inches (8-10 cm) when they’re born! A baby piggie’s weight will range from 2 to 4.5 ounces (60-130g), depending on birth order and litter size.

The average weight at birth is 2.8 ounces (80 g). The young guinea pigs will be smaller the larger the litter. Litters can have anything from one to eight babies, with three being the norm.


Guinea pigs develop at a similar rate, albeit it varies depending on the breed. Males develop quicker than females and end up weighing a few hundred grams more. Females and males are rarely the same sizes in most breeds.

While nutrition can influence the development rate, given the right diet, all guinea pigs should grow at the same pace. The majority of guinea pigs will continue to grow for at least 14 months. However, around 14 weeks, their growth slows significantly, and you can roughly estimate their mature size. After that, they won’t get any bigger.


How big is a full-grown American guinea pig?

The American guinea pig can weigh anywhere between one and three pounds. In adulthood, most guinea pigs weigh between 1.5 and 2.5 pounds, with males outweighing females. Males, on the other hand, are usually taller than girls. At maturity, the length ranges from 8 to 12 inches.

What type of guinea pig stays small?

Ridgeback guinea pigs are the tiniest guinea pigs, with some adults measuring only five inches long.

How long until Guinea pigs are full-grown?

By the age of 18 months, your guinea pig will be completely developed, measuring between 8 and 12 inches from snout to tail. A healthy diet consisting of timothy hay and guinea pig pellets, with a few nutritious morsels of fruits and vegetables that are abundant in Vitamin C tossed in for good measure, will benefit fully grown pigs.

How big is a full-grown guinea pig?

Guinea pigs are big-sized rodents that, on average, weigh between 800 and 1,300 g (1.6 and 2.7 lb) and measure between 20 and 25 cm (8 and 10 in) in length when fully grown.

About the author

I'm Gulshan, a passionate pet enthusiast. Dive into my world where I share tips, stories, and snapshots of my animal adventures. Here, pets are more than just animals; they're heartbeats that enrich our lives. Join our journey!