How Firm Should Your Child’s Mattress Be?

Posted by Pam Johnson - Head of Buying on 21st Jul 2023

How Firm Should Your Child’s Mattress Be?

Curious about how firm your child’s mattress needs to be? Here we explain all that need-to-know info.

Ensuring your child has the right support levels while they sleep is a must for most parents. But how firm should your child’s mattress actually be?

As with most aspects of life, a child’s mattress firmness needs will change as they move through the different stages of development. In this guide, we’ll explain why ensuring your child has the right levels of support is so important. We’ll also take you through the key stages at which their sleep support demands will change.

Read on to learn just how firm your child’s mattress should actually be.

Why is choosing the right mattress firmness for your child essential?

Getting a good night's sleep is imperative for promoting mental and physical wellness for everyone, especially children. Your child relies on a regular 8-16 hours every night (depending on their age) (1) to ensure that both their physical and cognitive development is properly supported.

Your little ones spend plenty of time in their bed, be it while they’re sleeping, chilling out or simply playing. With this in mind, picking out the right mattress for your child plays a key role in their everyday comfort.

But what is the right choice for your mini me? Well, that comes down to a series of factors. Let’s learn a little more to help us on the road to finding out how firm your child’s mattress needs to be.

Two children lay on a bed reading a book together

How can I choose the right mattress for my child?

When considering which mattress is ideal for supporting your child and promoting positive development through rest and recovery, there are four main things to consider. These are:

  • Age: The age of your little one will really dictate what options are available. And, which mattress and how firm it should be is the right choice.
  • Their preferred sleep position: Just like with adults, kids have a go-to sleeping position. And that will tell you the level of firmness their mattress needs to be.
  • Allergies: If your child suffers from any allergies or skin irritations such as Asthma, Hay Fever or Eczema, you will want to consider investing in a hypoallergenic mattress. This will ensure they sleep easier and in turn, you will too.
  • Temperature control: Some children run hot. Others run cold. Just like adults, promoting sleep wellness means shopping for a mattress that works with your child’s core temperature is key.

Once you’ve considered all of the above, you’ll be in a much better position to choose the right mattress for your child. Let’s explore the general needs of children at various different ages next.

How firm should my toddler’s mattress be?

As your little one moves on from the realm of babies and into the toddler stage, you may feel moving your little one into a more grown-up bed is a good move. This is when a new child’s mattress will be needed. As with babies, back sleeping is widely regarded as the safest sleeping position for toddlers. As such, a medium-firm to firm mattress is the best choice.

How firm should my primary school aged child’s mattress be?

As your child hits the ages of around five, the transition to a larger kid's bed will inevitably begin. That said, parents are very instinctive where their child is concerned and thus, they – and only they – will know when that time has arrived.

As this transition often aligns with their move to big school (AKA primary school), ensuring they have a supportive mattress to get the sleep they need is absolutely essential. When they start school, kids are often physically and mentally exhausted by the end of their school day. That’s where the right mattress firmness really plays its part.

Single kids' mattresses are the perfect choice for this age. Not only because they accommodate growing bodies and are a space-efficient choice but, they are also available in a range of firmness ratings ranging from soft to extra-firm.

But, how firm should your child’s mattress be?

Well, generally a medium-firm or firm mattress is the ideal for children. This is because it helps in supporting their spinal alignment during periods of growth. A medium-firm mattress is usually the best choice as it offers continuous support as they switch from one sleeping position to the next throughout the night.

You’ll also want to consider choosing a mattress that features cooling properties for your child. This helps to stabilise their body temperature while they sleep and ensures they wake up feeling well rested and ready to tackle the next day head on.

How firm should my teenager’s mattress be?

When your child reaches their teenage years, their preferred sleep position should be at the forefront of your mind when choosing how firm their mattress should be.

Choose a mattress that is firm enough to support their spine, shoulders, neck, hips and legs during their continued development. But also, choose one that is soft and comfortable enough to not cause any joint pain. Growing pains put enough strain on a teenage body. Add to that the effects of puberty and changes in hormones and you can see why the right firmness of mattress is a must.

An amazing product to consider is the Slumberland Flip 2-in-1 mattress. This adaptable sleep support solution has been specifically designed with growing bodies in mind. It will deliver support for your pre-teen right through to adulthood. By utilising innovative variable geometry springs that offer different comfort and support on each side of the mattress, this choice is ideal for your child’s growth development. Simply flip the mattress to suit your child’s comfort and support needs. Tailor their sleep support to your teen’s individual, weight, height and sleep preferences.

Now is also the time to consider switching their single bed out for a double. Your child’s teen years is actually the fastest stage of growth they’ll face and it’snot uncommon for us to discover our children have outgrown their old mattresses all of a sudden.

Look out for any growth spurts in your teen and be sure to keep an eye on whether their bed is still the right size. Remember, their mattress can only be as big as the bed frame accommodates, so now is the best time to consider an upgrade.

Memory foam, hybrid and latex mattress are all particularly designed to help support proper spinal posture for your teenage child while they sleep, whichever their preferred sleep position.

What else should I consider when choosing a mattress for my child?

When picking out a mattress for your child, along with the firmness, there are a few other things to think about. Let’s explore this a little more:


Some children run hot, while others run cold. This is always ten-fold during the night. Whether it’s down to a bout of warm weather, or just cause your little one is a fidget midget, keeping their temperature regulated while they sleep is essential to ensure rejuvenation! If your little one has trouble regulating their body temperature while they sleep, consider iGel.

iGel mattresses have been specifically designed with regulating body temperatures in mind. Plus, they’re available in both single and double mattress sizes.

An iGel mattress achieves a comfortable sleep temperature of between 35 to 37° Celsius. This allows your child’s body to relax and enter an undisturbed (at least due to temperature) deep sleep. When we overheat, our body’s internal air conditioning system kicks in to cool us down. And so, we sweat more. This quickly reduces our sleep quality and leaves us sweaty. Plus, when we get too cold, we can be easily woken from our deep sleep. This is true too of our little ones.

Our new formula iGel™ Advance with Graphene Technology is the only material proven to absorb, store and release heat to keep our bodies at the optimal temperature while we sleep, whatever the weather.


When it comes to fidgeting, kids are defenceless. They can’t stop themselves and quite often, they’ll end up waking themselves up. This is when picking out a mattress with good shock absorption will help to stall this. A pocket sprung mattress is a particularly good choice for a fidgety sleeper. This is because it offers independent support from each and every spring. Memory foam mattresses also offer both support and comfort where and when they need it most.

That said, if your little one is a fidgeter and runs hot, it’s best to stick to the pocket sprung mattress options.

Bed wetting

Bed-wetting is something that happens to almost every child. With that in mind, it’s best to plan ahead. If your child has a bed-wetting tendency, try to choose a water-repellent mattress. So long as your child doesn’t have an allergy to latex, a latex mattress could be your best choice. This helps keep your child and their mattress clean while increasing the life of your investment.


Hypoallergenic or anti-allergy mattresses deliver comfort while relieving symptoms of allergies and asthma, especially in children. For anti-allergy mattress technology, there’s no better brand right now than Sealy. Sealy mattresses feature a Pro-Shield™ anti-allergy treatment that grants your little ones a clean, comfortable and allergy-free night’s sleep.

How long does a children's mattress last?

In general, mattresses last 8-10 years before needing to be replaced. This is true of both adult and child mattresses. So, if you choose to invest in a high-quality mattress, it should easily last your child from age 5 well into their teenage years. You can also pass it on to a younger sibling after your child has outgrown it too.

How thick should a child’s mattress be?

Generally, children need a mattress that is around 5 to 8-inches thick. As children are much lighter than adults, they don't need a super-thick mattress to provide the right levels of comfort and support. If the mattress is to be used in a bunk bed it should be no thicker than 15cm to ensure sufficient safety rail height,

That said, as your child moves into pre-teen years and beyond, investing in a thicker mattress that will offer more support for their growing bodies is a wise idea.

How to clean a child’s mattress

Bed-wetting is an inevitable part of growing up. If your child has wet their bed and you are wondering how best to clean it, there are some simple steps you can take using a handful of ingredients from your kitchen cupboards.

  1. Start by stripping the bed. Yes, we understand this is an obvious first step but felt it was worth the mention anyway.
  2. Reach for the baking soda. Sprinkle baking soda on the affected area. And, remember to avoid rubbing at the stain as it’ll only work the pee deeper into your child’s mattress.
  3. Mix up a solution of washing powder and water. Bio works best in stain removal. Alternatively, you can use white vinegar so long as you don’t mind the smell! Mix approximately one part water with one part vinegar or washing powder.
  4. Spray the stain. Spray the solution you’ve made up onto the stain and leave it for 3-5 minutes. Make sure you use enough of the solution to completely cover the surface of the stain.
  5. Blot up any excess moisture. After you’ve waited 3-5 minutes, use a towel or some kitchen roll to soak up any moisture left on the surface of the stain.
  6. Reach for the baking soda again. Next, you want to sprinkle baking soda over the whole mattress. After this step, you’ll need to allow enough time for your child’s mattress to dry out completely. This tends to take at least 18 hours which means you’ll have to find an alternative sleep solution for your little one for one night.
  7. Clean off the baking soda. At least 18 hours have passed, so now it’s time to clean up all the baking soda using a soft brush. Once that’s done, pop the mattress in an upright position either outside or in a well-ventilated room to air it out. 


  1. Sleep hygiene in children and young people | Great Ormond Street Hospital (
authors profile
Pam Johnson
Head of Buying
Pam has worked within Bensons for Beds for 16 years and has a great deal of experience in both developing and sourcing new product ranges. As Head of Buying specialising in mattresses, divans and headboards, Pam is dedicated to providing solutions that help customers to get a great night’s sleep.
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