How Big Do Guinea Pigs Get? A Guinea Pig Size Guide

How Big Do Guinea Pigs Get?

Welcome To Our Complete Guinea Pig Size Guide. How Big Do Guinea Pigs Get? What Does A Full Grown Guinea Pig Look Like? And Does Their Size Differ Depending Upon Their Breed?

We will be finding out the answers to all of these questions and more today.

Just like with any animal, adult guinea pig size can vary based on a number of factors.

These could include birth order, age, species, gender, diet, lifestyle, overall health and genetics.

This makes the topic of how big can guinea pigs get quite interesting, and it is one we will explore in depth here in this article!

How big do guinea pigs get?

So how big do guinea pigs get, precisely? There is no one “set” answer to this question, but there are helpful guidelines you can learn about.

A guinea pig’s size consists of length, width, height and weight.


Guinea Pig Size Guide - How big do guinea pigs get?

Most commonly, however, only length and weight are noted when measuring how big do guinea pigs grow.

As far as guinea pig senses are concerned, it is also worth noting that, while guinea pig big eyes are common across breeds, eyesight is not their keenest sense.

Guinea pigs are much more noted for their finely tuned sense of smell!

As well, adult guinea pig size can vary in each of the following areas depending on if it is a boy or a girl pig.

Guinea pig weight

Here, let’s use weight as one example of the many variations in how big can a guinea pig grow.

An adult lady guinea pig generally weighs between 608 grams (1.5 pounds) and 1,130 grams (2.5 pounds).

Whereas an adult male guinea pig generally weighs between 910 grams (2 pounds) and 1,360 grams (3 pounds).

The vast majority of adult guinea pigs will weigh somewhere between 700 grams (1.5 pound) and 1,200 grams (2.6 pounds). Although there will always be petite or very big guinea pig exceptions to this guideline!

For more on the specifics of guinea pig weight by gender and at different ages in the guinea pig life cycle, we invite you to review this informative post!

Full size guinea pig

So how big do guinea pigs get as fully grown adults?

As with hamsters, birds, dogs, cats, and other popular household pets, there are several different breeds of guinea pig that are kept as pets today.

Some pet piggies come from quite big guinea pig breeds, while others hail from lineages that are much more petite in their adult size.

Unlike many other related animals in the rodent family, most guinea pigs do not have a visible long tail that can count towards its overall length.

Which is actually good, since this can be really confusing when the tail length represents half of the rodent’s overall length!

For guinea pigs that do have visible tails, they are still usually only between 1 inch (2.54 cm) and 1.5 inches (3.81 cm) long. And are often mostly hidden from sight by the guinea pig’s fluffy, furry coat.

Here, an adult average guinea pig size in length can range from 8 inches (20 cm) to a full 12 inches (40 cm).

Biggest guinea pig breed

The award for the biggest guinea pig breed goes to the Rex guinea pig, which can grow up to 17 inches (43 cm) long at maturity!

To date, no other modern guinea pig breed even comes close to the Rex guinea pig’s incredible adult length!

But in general, the answer to “how big are guinea pigs?” will typically top out at between 10 and 12 inches in length.

Big guinea pig breeds

If you are curious about how big guinea pig get, you will be intrigued to know that most big guinea pig breeds grow across a length range of about 4 inches.

Guinea Pig Size Guide - How big do guinea pigs get?

And the larger pigs in each breed will range from 10 inches (25.4 cm) to 12 inches (20 cm).

Common and popular examples of big guinea pig animal breeds include these:

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

Abyssinian guinea pig size

One of the most popular and unique pet guinea pig breeds is the Abyssinian.

These wonderful piggies have a very stunning coat marked by cowlicks (“rosettes”) that create swirls of fur all over their body.

They also have lovely bands of color in their fur that can range from pure ivory to deep grey.

Abyssinian guinea pig size at maturity can range from 8 inches (20 cm) to 12 inches (40 cm) long depending on gender, birth order, diet and overall health.

American guinea pig size

The American guinea pig is considered to be one of the smaller breeds on the guinea pig size chart.

American guinea pig size tends to stay at the shorter end of the spectrum length-wise, with adult American guinea pigs reaching about 8 inches (20 cm) to 9 inches (22.86 cm) in length at maturity.

How big are baby guinea pigs?

If you think adult guinea pigs are cute, you should see them when they are babies!

Baby guinea pigs don’t stay babies for very long, however, so usually only breeders get to see these teensy versions of the adult pets we all love.

Guinea Pig Size Guide - How big do guinea pigs get?

If you are wondering how big are baby guinea pigs, well, an infant guinea pig may be only 3 inches (8 cm) to 4 inches (10 cm) long at birth!

Weight-wise, a baby piggie will only weigh between 0.13 pounds (60 grams) and 0.26 pounds (120 grams) depending on birth order.

But infant guinea pigs grow very fast…. In just 8 weeks, they will double in size and weight. In another 8 weeks, they will nearly double in size and weight yet again.

By the time a baby guinea pig is just over a year old, it will be at its full adult length and weight.

How big do female guinea pigs get?

It is generally possible to tell whether a guinea pig is a male or a female by the time a young pig reaches the age of three weeks.

The most common way is to palpate the abdominal area, but size can sometimes also be an indicator of gender.

For instance, when trying to determine how big do female guinea pigs get, it can be helpful to know that males can be longer and weigh more than females.

Most female guinea pigs will typically top out at between 8 (20 cm) and 10 inches (25.4 cm) in length when fully grown.

How big do male guinea pigs get?

In contrast with female guinea pigs, male guinea pigs often tend to be bigger (longer) and also heavier than their female counterparts.

Many first-time guinea pig owners who bring home a male piggie are quite curious about how big do male guinea pigs get.

In most breeds, the male guinea pig will be the one more likely to grow to that breed’s maximum length.

So for instance, if you have brought home an Abyssinian, you know that Abyssinian guinea pig size ranges from 8 inches (20 cm) to 12 inches (40 cm).

A male Abyssinian guinea pig will be more likely to grow to the full 12 inches in length than a female.

World’s biggest guinea pig

If you can imagine a guinea pig that weighed 1,543 pounds (700 kg) and stood 1.4 yards (1.3 meters) tall, you are imagining Phoberomys pattersoni, the biggest guinea pig ever, which lived 8 million years ago in what is now north Venezuela.

Phoberomys is now officially considered to be the world’s biggest guinea pig, although scientists are still piecing together how it evolved into today’s pint-sized relatives!

Unlike modern guinea pigs, this really big guinea pig also had a really long tail that it used for balance. Scientists say this biggest guinea pig that ever lived ate mostly grasses just like its tiny modern cousins, just lots more of it of course!

How Big Do Guinea Pigs Get?

We hope this article has answered your questions about how big will my guinea pig get and provided you with lots of other interesting information and facts on guinea pigs as well!

Most guinea pig owners don’t much mind whether their piggie grows up to be gigantic or pint-sized, record-setting or average.

After all, we love guinea pigs for their sweetness, their gentleness, their cuteness, their wonderful personalities and silky coats and friendly dispositions.

But when you love your guinea pig, you want to learn all there is to know about him or her too! We encourage you to keep learning, and also to share what you learn with other guinea pig enthusiasts. After all, keeping guinea pigs is the most fun when we are all learning together!

Further Reading and Resources

  • Guinea Pig Weight
  • Guinea Pig Cage Size
  • Hines, DVM, PhD, R., “Guinea Pigs as Pets” 2nd Chance, 2017.
  • Musser, G., “Guinea Pig: Rodent,” Encyclopedia Brittanica, 2017.
  • Bhattacharya, S., “Buffalo-Sized Guinea Pig Revealed,” New Scientist, 2003.
  • Hixon, J., “Cavia porcellus: Guinea Pig,” University of Michigan, 2011.


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