You may already be an expert on cavy care, from clean cages to the perfect diet. But not many piggy parents know that weighing their furry potatoes every wheek is a great way to monitor their wellbeing. Taking the time to regularly pop your piggy on the scales is a crucial part of cavy care and a helpful way to keep an eye on their general health and catch anything unusual early on.
If you’re a little unsure about a healthy weight for guinea pigs, how to get guinea pigs to lose weight, how to get guinea pigs to gain weight, and - most importantly - how to even get them on the scales, don’t worry. This guide to guinea pig size has got all the info you could need.
How big is a fully-grown guinea pig?
Just like us humans, guinea pigs come in all shapes and sizes. And while male guinea pigs are usually a little bigger and heavier than female guinea pigs, an adult piggy’s size and weight vary depending on their breed and age, and also their diet and exercise. What could be a normal weight for one might be underweight for another!
Let’s have a look at some general guidelines for a healthy weight for guinea pigs depending on their gender.
How big do female guinea pigs get?
As a general rule of thumb, female guinea pigs are a little smaller and lighter than the males. An average weight for a grown-up female guinea pig is around 2 lb to 2.5lb (900g to 1100g).
This female guinea pig weight chart is a great point of reference for the growth journey your floofs will go on:
How big do male guinea pigs get?
Boars are normally a little bigger and heavier than their female counterparts. A healthy weight for a grown-up male guinea pig is between 1000g to 1500g (2.2lb and 3.5lb). As always, these numbers vary depending on multiple factors, so bear in mind that some guinea pigs may be lighter or heavier than these averages but still be perfectly healthy.
Here’s your male guinea pig weight chart, a fantastic point of reference:
Guinea pig’s weight is linked to their breed
Your guinea pigs’ breed makes a big difference to their size. Smaller breeds, like Americans, weigh less because there’s less piggy to weigh. Larger breeds, like Peruvians, not only put more piggy on the scales, they also bring long hair along.
On a funny note, we’d just like to confirm that skinny pigs aren’t actually skinnier than other guinea pigs. Yep, they lack the luscious locks of some of their cavy companions, but they’re not far behind when it comes to size or weight. The breed’s name is simply a reference to the amount of skin you’re seeing (and, let’s be honest, it’s a lot nicer than calling them naked guinea pigs!).
Here’s how the average weight of our most popular guinea pig breeds varies:
- Abyssinian: 900g to 1400g (2lb to 3lb)
- American: 700g to 1100g (1.5lb to 2.5lb)
- Peruvian: 900g to 1400g (2lb to 3lb)
- Texel: 700g to 1100g (1.5lb to 2.5lb)
Who is the biggest guinea pig?
The biggest pet guinea pig breed is the Rex, which weighs up to 1400g (3lb) and is 18 inches long. These piggies are larger than most, so their piggy parents should take extra care when it comes to weight checks and diet. The Rex guinea pig is known to gain weight quickly, so a weekly check-up can help keep them at a comfortable and healthy weight.
However, outside of the pet guinea pig sphere, we can find even bigger piggies. Cuys are massive guinea pigs, often twice as large as our pet piggies, weighing around 1800g to 3600g (4lb to 8lb). They're also extremely skittish and have a much shorter lifespan than pet guinea pigs. But aren’t they just magnificent?
Who is the smallest guinea pig?
On our list of smallest guinea pig breeds, we’ve got the Texel and the American guinea pig. American guinea pigs only grow to around 20cm to 22.5cm (8in or 9in). The sweet Texel guinea pig is quite similar, measuring around 20cm to 25cm (8in to 10in).
Both breeds weigh around 700g to 1100g (1.5lb to 2.5lb), and it’s a good idea to monitor their weight closely. Piggy parents wouldn’t want their smaller floofs to become underweight or overweight!
How big are baby guinea pigs?
If you’ve never seen a baby guinea pig (treat yourself and look up some adorable photos!), you’ll be surprised to learn that they're born with a full coat and ready to go. In fact, baby guinea pigs grow (and gain weight) pretty quickly.
A newborn guinea pig can weigh anywhere between 60g and 120g (2oz and 4 oz). Just like adult guinea pigs, a baby piggy’s weight varies depending on their breed. Then, as they get bigger quickly, they can gain an extra 30g to 50g (1oz to 1.5oz) per week in the first 8 weeks of their lives.
When they reach 16 weeks of age, their weight will go up to between 360g and 480g (13oz and 17oz) as most will be with their new piggy families already. Then, baby piggies that reach 6 months of age will end up weighing around 500g to 700g (17.5oz to 25oz).
Just before a baby piggy reaches one year of age, they’re fully mature - meaning they’re done growing. At that point, they should reach a good average weight for their breed. Younger guinea pigs are more active than their older piggy friends, so it’s normal for them to be a little lighter.
But if you notice a sudden drop or rise in their weight, it’s a good idea to speak to a vet as it could be a sign that your floofs aren’t feeling their best.
Why should I watch my guinea pig’s weight?
It’s simple, really. Like all animals, a guinea pig’s weight is an important indicator of their general health. Let’s face it, guinea pigs are walking stomachs - they eat non-stop! But when a piggy is unwell, they tend to eat less, meaning that they burn more body fat for energy and start to lose weight.
As prey animals, guinea pigs are generally very adept at hiding symptoms of illness in order to avoid appearing weak to predators. But the one sign of illness that they’re unable to conceal is weight loss!
By weighing your guinea pig regularly, you can keep track of their weight and well-being so that you can take action when needed. Another thing to bear in mind is that guinea pigs are sensitive little souls who can become depressed - for instance, when they lose a cage mate. If your piggy is feeling blue, this can cause them to stop eating and lose weight too.
How exactly should I weigh my guinea pig?
If you already have guinea pigs, you’ll know that these tiny tornadoes rarely stop hopping about their homes - apart from nap time, of course. But how on earth are you meant to pop them on a scale?
Never fear, brave piggy parent, we’ve got a step-by-step guide to make the weekly weighing sessions a success with every piggy!
Step 1: Choose your scales
When it comes to your piggy scales, you’ve got the choice of analog or digital scales, and it’s really down to your own preference. Just remember that the scale should be big enough to welcome your pet.
Once you’ve found the right scale for you and your floofs, it’s a good idea to store it near your piggies’ palace and keep it for the weekly weighing only. After all, if you’re using your baking scales, there’s a chance your pigs could find a bit of leftover batter - or they could leave a little something behind for your next baking session. You see where we’re going with this, right?
Step 2: Get ready to weigh!
Before you get your pigs, make sure to pop the scales on a safe, flat surface. Some of our furry friends won’t want to stay on the scales, so it’s best to prepare for them hopping off. It’s also helpful to pop your piggies in a box when weighing, so they’re secure. Remember to take off the box’s weight from your final reading.
If you’re sure that everything’s set up safely, it’s time to get the pigs!
Step 3: Keep track of their weight
Track your guinea pig’s weight by entering the results for each weigh-in on a calendar, spreadsheet, notebook or an app. If you need to take your piggy to the vet, don’t forget to also take along a copy of their weight tracker to help with any medical assessments.
What about tracking my pregnant guinea pig’s weight?
A pregnant guinea pig almost doubles her pre-pregnancy weight - and no wonder, if she’s carrying several baby floofs around! During this time, it’s a good idea to keep a close eye on the piggy’s weight to make sure she eats enough and has everything she needs. The weight is also a good indicator of any reason for concern and a vet visit (even though pregnancy calls for regular check ups either way!).
A pregnant sow needs some extra support during this time, since being piggy pregnant is hard work. More than ever, she’ll need vitamin C in her diet and lots of leafy greens to soak up the good nutrients.
Your female piggy will also get pretty big, so it’s important to keep her in a comfortable and quiet environment, so she can rest and relax. Remember that guinea pigs can get pregnant shortly after giving birth, so keep your male piggies separate.
What if I can’t weigh my guinea pig?
If you can’t get hold of a set of scales for whatever reason, you can get a pretty good idea of whether your guinea pig is losing or gaining weight by keeping a close eye on them and handling them often.
Measuring your guinea pig’s ‘heft’ (another word for ‘weight’ or ‘size’) is a useful way of recognising if they’re healthy or not. You can do this by holding your furball and gently checking around their spine, hips and ribcage.
You should be able to feel the outline of these bones through their fur and body fat. If you can’t feel any bones at all through your piggy’s podge, they may be overweight. While if their hips, ribs and spines appear to be jutting out a bit too much then your guinea pig may be underweight.
There are also other signs that may indicate a weight problem - if your piggy is struggling to walk, their stomach touches the floor when they’re standing or they appear to have less energy, then something may be amiss.
Remember that a long-haired coat can make it harder to spot weight changes as well as other signs such as thinness and protruding ribs - which makes it even more important to do regular weigh-ins. To give you a visual idea of your guinea pig’s size, check out this handy infographic by UK Pet Food.
How often should I weigh my guinea pigs?
Weighing a guinea pig once only tells you how much they weigh at that precise moment and doesn’t alert you to any potential weight gain or loss. For that reason, it’s important to make regular weigh-in sessions part of your piggy’s care routine. The frequency will depend on which stage of life they’re at.
Here are some easy-to-follow tips for creating a successful guinea pig weight tracking routine:
- Create a schedule and stick to it.
- If your guinea pig is in good health, perform weekly weigh-ins as a routine health check.
- Weigh your piggy at the same time and day each week to keep tracking consistent.
- Weigh newborn piggies daily over the course of their first few weeks and then progress to weekly weigh-ins to ensure they’re gaining weight.
- If you’re concerned about your guinea pig’s health, weigh them daily so that you can quickly recognise - and act on - any worrying weight changes.
Should I worry that my guinea pig’s weight has changed?
A piggy’s weight can go up and down a little, depending on how full their stomach is or how they’re feeling that day - just as it does for us humans. But let's look at what is considered to be an acceptable weight change, and when it might be a cause for concern:
- If your piggy’s weight either drops or increases by 25g (0.8oz) in a week, it can be pretty normal, so just continue weighing your piggy weekly to keep track of things. However, if you notice that your piggy’s weight routinely drops or gains 25g (0.8oz) between weigh-ins, then it may be time for a vet visit to rule out any health problems.
- If you notice that your piggy has lost or gained 50g (1.7oz) it’s important to keep a close eye on them. Start weighing them daily so that you can quickly recognize any more sudden weight changes and get them checked out by a vet if necessary.
- If your guinea pig’s weight drops or increases by 75g (2.6oz) it’s time to take action as that’s a pretty big change. Get them booked in with the vet.
- A sudden weight loss or gain of 100g (3.5oz) would be considered an emergency in terms of your guinea pig’s health, and you should take them to the vet as a matter of urgency.
Help, my guinea pig is too big!
While wild piggies spend all day foraging and running across huge grassy areas, pet piggies are limited to their indoor guinea pig cage. It’s easy for our furry friends to become couch potatoes and simply spend their days in bed, snacking away.
If you notice your floofs are getting a bit too round, think about their living environment. Do they have enough space to run about? Is there anything in their home that entertains them and encourages more exercise? Are they eating the wrong food?
If you’re wondering how to get guinea pigs to lose weight, your quickest and best shot is more exercise and the right diet. Upgrading their cage and also making time for daily out-of-cage play sessions are a great starting point. Often, however, this can also be an indication of underlying health issues so it's always best to consult your vet.
How to get guinea pigs to lose weight
If your piggy consumes more calories than they burn through activity, they will gain weight. There are several ways you can help your guinea do the opposite and lose weight:
- Don’t exceed the daily recommended amount of food (portioned pellets, fruits and veggies).
- Limit the amount of fruit you feed your guinea pigs as they’re full of sugar.
- Avoid feeding your guinea pig unhealthy snacks and treats which are usually high in sugar and other unhealthy ingredients.
- Take a look at our free Kavee care guide for more guidance on how to feed your guinea pig a healthy diet.
- Provide daily floor time (two hours a day if possible) to increase your guinea pig’s exercise and activity levels.
- House your guinea pig in the largest cage possible to provide plenty of space for exploring (bear in mind that small pet shop cages prevent piggies from exercising!).
- Provide chew toys and other enrichment opportunities such as our tunnels, ramp and lofts.
- Double-check any female piggies to see if they’re pregnant - in which case they’ll need extra nutrition and support.
Help, my guinea pig is too thin!
Losing weight and becoming underweight can be a real concern for guinea pigs - they can lose weight rapidly, which puts them at a higher risk of developing dangerous health complications, including:
- Decreased immune function.
- Malnutrition and vitamin deficiencies.
- Anemia.
- Growth and development issues.
- Higher risk recovery from surgical procedures.
- Hypothermia due to the guinea pig not having enough body fat to keep warm.
- Fur, skin, and teeth problems.
Why is my guinea pig losing weight?
If you've noticed your guinea pigs are losing weight, it’s a cause for concern. Our furry friends eat all the time because of their quick metabolism, so they shouldn’t be losing weight without a reason. It might be due to the following factors:
- Wrong diet: do they have access to a big pile of hay all the time? Do you feed healthy veggies and high-quality pellets every day?
- Lack of food: some new cavy parents don’t realise that their piggies need food all day long. Make sure hay is always available, and other healthy snacks and pellets are available throughout the day.
- Stress: piggies are stressed easily, either by rough handling, a busy environment, or unsuitable living conditions - and that can affect their appetite. Can you move them to a quiet, large cage that lets your floofs relax, so they can eat safely?
- Health issues: the real troublemaker when it comes to losing weight are health issues. Anything from an infection to poor dental health can have an impact on your piggies’ weight, so a vet visit can help you rule any of these out.
How to help guinea pigs gain weight
First things first, check your guinea pig’s food intake. Are they really getting a great diet with sufficient nutrition or do you need to increase their calorie intake? Oat flakes and small slices of banana are some of the best food for guinea pigs to gain weight, though they also come with some additional needs.
When piggies eat oat flakes, they need to drink more, because the flakes soak up the water they’ve drunk. Bananas are healthy but high in sugar, so be careful about feeding more than the odd slice. Some piggies may be suspicious of these new foods at first, and any new additions to their diet should be gradually introduced to avoid upsetting their tummies.
Make sure they have access to these foods every day to help them gain weight:
- Hay: it’s the key component to a brilliant piggy diet. Timothy hay is the best choice for piggies, but you can add some oat hay to their diet while they’re building up a little piggy chunk.
- Veggies: piggies have them every day, and you can add an extra slice of carrot to their diet while they’re gaining weight.
- Pellets: there are lots of guinea pig pellets out there, and choosing a high-quality brand will help your piggies reach and maintain a healthy weight.
But food is not the only lifestyle choice that makes a big difference in your piggies’ wellbeing. Keeping them at a comfortable temperature between 18°C to 23°C (65°F to 73°F) means the furry friends don’t need to use up extra energy to stay warm - which could lead to weight loss.
Any injury or illness can also affect their appetite, so it’s a good idea to check them for anything unusual regularly. Teeth issues, in particular, are a real culprit when it comes to weight loss. And if your piggies are off their food, it’s important to act quickly because the situation is critical. If in doubt, contact your vet and let them show you how to syringe feed your floofs until they’re better.
Weight loss in piggies is not to be taken lightly, and it’s a good idea to keep an eye on their eating habits as well as their weight.
FAKs on Guinea Pig Weight and Size
How big is a fully-grown guinea pig?
The average weight for a female guinea pig is around 900g to 1100g (2lb to 2.5lb). A healthy weight for male guinea pigs is between 1000g to 1500g (2.2lb and 3.5lb). Remember that these numbers are just a point of reference because every piggy is different.
Do guinea pigs lose weight as they get older?
Yes, guinea pigs often lose weight when they get older because their metabolism slows down. When they eat less, they lose weight. Some of the best food for guinea pigs to gain weight includes oat hay, though if they lose a lot of weight, older piggies should see a vet.
What is the best food for guinea pigs to gain weight?
The best food for guinea pigs to gain weight is oat hay, the right veggies, and high-quality pellets. A cavy-savvy vet can help set up a dietary plan for healthy weight gain for your piggies.
How big do female guinea pigs get?
Normally, an adult female guinea pig weighs around 900g to 1100g (2lb to 2.5lb). They’re usually between 20cm to 25cm (8in and 10in) long.
Remember that guinea pigs come in all shapes and sizes, like humans, so you may meet some female guinea pigs that are bigger or smaller than this.
How big do male guinea pigs get?
Adult male guinea pigs usually weigh around 1000g to 1500g (2.2lb and 3.5lb). They’re often a little bigger than female guinea pigs, though different piggy breeds come in different sizes.
