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Everything you need to know about your guinea pig and their weight too fat too thin

Everything you need to know about your guinea pig and their weight

You probably know all about providing your guinea pig with plenty of hay and hideys. You may also be clued up on how often to clean out your piggy’s cage. 

But we have a question for you: when was the last time you weighed your guinea pig? Even if you know loads about guinea pig care, weighing your little furry friend might not be something you’ve ever thought about doing. But, actually, 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 wellbeing. 

Confused? Well, don’t be because we’ve answered all your questions about guinea pigs and their weight - as well as giving you the lowdown on how to actually weigh your guinea pig and keep track of their weight. 

why is it important to weigh your guinea pig sitting next to gold scales


Why is my guinea pig’s weight important?

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 generally walking stomachs - they eat non-stop! However, 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 popping your guinea pig on the scales on a regular basis, you can keep track of their weight and well-being. That way, if you notice an unexpected or worrying change, you can take appropriate action by making an appointment with a vet for a check-up. 

If you have baby guinea pigs, it’s really important to monitor their weight to ensure they’re gaining weight as expected. Bear in mind that for the first three days, a baby pig’s weight will fluctuate as they develop an interest for food. However, once they start gaining, they should continue to do so. If not, this indicates something may be wrong.

Pregnant sows and nursing mothers are particularly at risk of weight loss so by tracking their weight, you can keep an eye on things and ensure that they’re getting enough nutrients before and after birth.

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.

why should you weigh your guinea pig curly haired adult guinea pig with curly haired baby guinea pig on white background 

How often should I weigh my guinea pigs?

Weighing a guinea pig once only tells you how much they weigh at that precise moment. It 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. How often you weigh your piggy depends on which stage of life they’re at. Here are some easy-to-follow tips for creating a successful guinea pig weight tracker routine:

  • Be organized, 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
  • If you have newborn baby guinea pigs, weigh them 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 for any reason, weigh them daily so that you can quickly recognize - and act on - any worrying weight changes.

To help you keep track of your guinea pig’s weight, we’ve produced a free Kavee guinea pig resource pack, which you can print and use. Routinely track your guinea pig’s weight on a graph so that it is easy to visualize and quickly notice any changes. We’ve included some examples in the pack to help get you started!

How much should my guinea pig weigh? Is my guinea pig too fat or too skinny? 

As with humans, when it comes to guinea pigs, there’s no such thing as a ‘perfect weight’. After all, each piggy is unique. 

It’s also worth knowing that average weights can vary from one guinea pig breed to another. For example, Rex guinea pigs tend to be bigger than other breeds whilst American guinea pigs are at the smaller end of the scale. For the avoidance of doubt, ‘skinny pigs’ aren’t actually thinner than guinea pigs with lots of fur. These almost totally hairless guinea pigs are called ‘skinny’ because you can see a lot of their skin and they look more streamlined than hairier piggies!

If you have a baby guinea pig who is still growing, they may gain weight more dramatically some weeks than others due to growth spurts, which are perfectly normal. By 15 months, a guinea pig is generally considered fully grown and their weight should remain consistent from this point onwards with only minor fluctuations.

Many sources cite that the average weight ranges for adult guinea pigs are as follows:

  • Adult male: between 900g and 1200g
  • Adult female: between 700g and 900g

However, today, many pet owners will find that their guinea pigs will weigh in the top weight range, especially for female guineas. Below illustrates common averages reported by pet owners.

how much should my guinea pig weigh? guinea pig weight comparison averages for male and female guinea pigs

Do bear in mind that some guinea pigs may be lighter or heavier than these averages but still be perfectly healthy. By keeping a regular track of your guinea pig’s weight, you should be able to determine what is a healthy, consistent weight for them. After all, as a piggy parent, you know your fluffball best! 

Take a look at our Kavee weight charts for more guidance:

free printable graph to track guinea pig weight over time care sheet for boars

Free Boar Guinea Pig Weight Chart by Kavee

printable weight tracker graph for sows free guinea pig care sheets

Free Sow Guinea Pig Weight Chart by Kavee


Click here to download the printable version of the charts.

My guinea pig’s weight has changed. Should I worry? 

As we’ve already mentioned, you may notice your adult guinea pig’s weight fluctuates slightly from time to time. But what exactly is considered to be an acceptable weight change and when might a weight loss or gain actually be cause for concern?

  • If your piggy’s weight either drops or increases by 25g (0.8oz) in a week then try not to worry. Small changes in an adult piggy’s weight are actually 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 visit to see the vet to check everything’s in order.
  • 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. Check our list of recommended cavy vets in the USA to guide your choice. 
what should I do if there is a change in my guinea pigs weight? weight loss and weight gain changes in guinea pigs infographic chart guide

How exactly should I weigh my guinea pig? 

You may be wondering how on earth you should weigh your cheeky, wriggly little piggy! Follow our step-by-step guide:

  • Have a dedicated set of digital or analog scales stored close to your guinea pig’s cage for easy access. You can choose from a wide range of scales - from smaller kitchen scales to professional vet scales. 
  • Before you weigh your guinea pig, place the scales on a safe, flat surface - ideally on the floor - in case your guinea pig wriggles or tries to jump off.
  • Some scales have a curved weighing plate which your guinea pig can safely sit inside during their weigh-in. But if you’re using a scale with a flat surface, place your guinea pig in a bowl or box whilst they’re being weighed, ensuring that you take the container’s weight into account as this will obviously affect the final reading.
  • If you don’t have a small set of scales suitable for weighing your guinea pig on their own, you can weigh yourself first and then and weigh yourself holding your guinea pig. Deduct your weight from the total weight of you and your piggy together in order to get your piggy’s weight. Bear in mind though that the best, most accurate way to know your guinea pig’s weight is by weighing them on their own on a set of scales suited to them.
  • Track your guinea pig’s weight by entering the results for each weigh-in on a calendar, spreadsheet, notebook or an app on your phone. 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.
How to weigh guinea pigs examples of digital scale or mechanical scale to weigh guinea pigs to track health

What if I can’t weigh my guinea pig?

In a perfect world, every guinea pig parent would have a set of weighing scales close to hand and we’d recommend that you buy an inexpensive set if possible. As we’ve already explained, regular weigh-ins are the most accurate way to track your guinea pig’s weight.

However, the truth is that we don’t live in a perfect world. So 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 recognizing 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. On the other hand, 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. 

If you have a long-haired guinea pig, remember that those flowing locks 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 Guinea Pig-Size-O-Meter infographic from pet food manufacturers association, PFMA .


what if I do not have a scale to weigh my guinea pig Guinea Pig-Size-O-Meter infographic from pet food manufacturers association, PFMA


Guinea Pig-Size-O-Meter infographic from PFMA

Guinea Pig-Size-O-Meter infographic from pet food manufacturers association, PFMA

Guinea Pig-Size-O-Meter Rating Chart infographic from PFMA

Help, my guinea pig is too fat! What should I do about it?

Yes, we all love our cuddly little pals but there is such a thing as TOO cuddly, you know! Just as being seriously overweight can cause health complications for humans, obese guinea pigs are a much higher risk of developing nasty issues including:

  • heart problems
  • diabetes
  • back pain
  • high blood pressure
  • digestive problems
  • bumblefoot foot infection caused by extra weight and increased pressure on tender footpads
  • urine scald (hutch burn) caused by urine soaking into the guinea pig’s fur and skin because they’re immobile
  • pressure ulcers (bed sores)
  • fly strike and other pests, which will be attracted to a dirty guinea pig who is too fat to groom themselves properly
Help, my guinea pig is too fat! What should I do about it? complications of weight gain for guinea pigs quick reference chart

How can I stop my guinea pig getting fat?

It’s simple really - if your piggy consumes more calories than they burn through activity, they will gain weight. So there are a number of ways you can prevent your guinea becoming obese:

  • 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 it’s laden with 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 sheets 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 (such as one of our Kavee modular cages) in order 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 Kavee ramp and loft kit and fun campervan and tank play set.
How can I stop my guinea pig getting fat? tips to help prevent obesity in guinea pigs quick reference chart guide

Help, my guinea pig is too thin! What should I do about it?

Losing weight and becoming underweight can be a real concern for guinea pigs - weight can be lost rapidly which puts them at a higher risk of developing potentially fatal 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

help my guinea pig is too thin quick reference chart for complications of an underweight piggy

How can I prevent my guinea pig from losing weight?

First things first; assess your guinea pig’s food intake. Are they really getting a balanced diet with sufficient nutrition or do you need to increase their calorie intake?

  • feed nutritious treats like oat flakes and slices of banana as supplement foods
  • introduce new foods gradually as guinea pigs don’t adjust well to change and may be fussy with new tastes - if they turn their noses up first time, try again another day
  • download our free Kavee care sheets for more guidance on the ideal foods your guinea pig should eat to thrive
  • keep your guinea pig’s living space at the correct temperature (between 17°C and 20°C/ 60°F and 68°F) - if their cage temperature is too low, they may burn more energy and lose weight more quickly burning fat in order to keep their bodies warm
  • hold your guinea pig often and check them over or signs of ill health such as cuts or rashes - whilst guinea pigs will often hide illness or injury, they tend to stop eating when something’s wrong and can lose weight rapidly as their gut motility stops working
  • if your guinea pig is refusing food, you may need to syringe feed them - check out our guide to critical care here
  • If you have serious concerns about your piggy, take them to a vet - check our list of recommended cavy vets in the USA to guide your choice

How can I prevent my guinea pig from losing weight? quick reference guide to help a thin guinea pig


Here at Kavee, we understand that guinea pig sizings can be an, ahem, weighty topic but we hope we’ve explained the basics in our guide to weighing your guinea pig. By keeping track of your guinea pig’s weight, you can stay clued-up on their general well-being and keep them safe and healthy - which is all we really want for our precious piggies isn’t it?

the importance of weighing your guinea pig on a weekly basis vet completing guinea pig check up

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