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Can you sleep on a mattress while it is expanding?

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A mattress can take between 2 to 72 hours to fully expand. It’s recommended that you let it reach its full dimensions before using it, as sleeping on it during expansion may impact its feel and performance.

Sleeping on a new mattress can be exciting, especially if your old one is uncomfortable. Many new mattresses are compressed and rolled up to fit into conveniently sized packaging for delivery.

These mattresses need to be unrolled and given some time to expand. As tempting as it is to use the mattress straight away, it’s advisable to allow it to fully expand to its actual dimensions before using it. Sleeping on a mattress while it’s expanding may affect how it feels and performs.

Man unrolling new mattress on slatted bed frame

Why are mattresses compressed?

Not too long ago, buying a new mattress meant heading to your local store. However, bedding manufacturers had to adjust as shoppers became more comfortable purchasing big-ticket items online. Selling mattresses online posed several challenges initially. Convincing shoppers to buy without testing was one hurdle. Furthermore, mattresses are bulky, making streamlining the delivery process challenging.

Manufacturers focused on ways to fold mattresses without compromising quality or comfort. This led to the creation of the mattress-in-a-box concept.

Mattresses are compressed primarily for easier shipping and handling. Compressing a mattress reduces its size, allowing it to fit in a box or tube for transportation, which can be delivered directly to the customer’s home. The compression process helps reduce delivery costs and ensures mattresses are easier to manoeuvre. This is especially beneficial for homes with access restrictions, such as narrow stairs and tight corners, where traditional flat mattresses might be difficult to manoeuvre into the bedroom.

Many online mattress retailers offer generous return policies, allowing customers to test the mattress at home for an extended period. If unsatisfied, customers have the option to return it to the seller. Compressed mattresses are much easier to repackage and return than traditional mattresses.

How long does a mattress take to expand?

It can take anywhere from 2 hours to 72 hours for a mattress to fully expand. The exact timeframe depends on the type of mattress and its materials. For example, thick memory foam and hybrid mattresses may take longer to decompress.

What are the potential issues of sleeping on a mattress while it is expanding?

While some manufacturers allow sleeping on a mattress before it fully expands, doing so can cause several issues.


A mattress that hasn’t fully expanded is unlikely to provide enough cushioning and may not conform well to body shape. Initially, it can feel overly firm, leading to painful pressure points and discomfort.

Poor support

A rolled-up mattress is unlikely to provide adequate support if you sleep on it straight away. The body may not sufficiently sink into the mattress, resulting in misalignment. Some sleepers might feel the base underneath the mattress, a sensation known as ‘bottoming out’.

Furthermore, excessive weight or force could damage the bed base underneath, as a compressed mattress does not provide sufficient cushioning.

Poor quality sleep

Sleeping on a rolled-up mattress before it fully expands can lead to poor-quality sleep, as it may not offer enough comfort or support. Consequently, you might wake up feeling tired, irritable, and stiff. 


Using a mattress before it fully expands can lead to premature wear and tear and compromise its lifespan. Indentations and sagging may be noticeable, resulting in an uneven sleeping surface. Furthermore, the mattress might not return to its original dimensions. You cannot do much with a sagging single-sided mattress except replace it.

Invalidate the mattress warranty or guarantee

Sleeping on the mattress before allowing it to expand could invalidate its guarantee or warranty.

How to ensure your mattress is expanding properly

Refer to the manufacturer’s instructions for guidance on unpacking and setting up your new mattress. Here are some general steps to follow:

Clear the space

Compressed mattresses come in neat, compact, vacuum-sealed packaging. Before unpacking, remove any items, such as pictures, rugs, and light fixtures that might be in the way so there is a clear path to the bedroom.

Remove the old mattress and any other items that might interfere with unpacking the new mattress to ensure you have plenty of space to work with.


Remove the mattress from the box and place it on your bed base. Carefully cut the plastic mattress wrapping with scissors, taking care not to cut into the mattress.

Avoid propping the mattress on its side, as this can put unnecessary strain on the components and cause the mattress to sag or lose its shape. Always keep the mattress flat and supported.


After removing the plastic wrapping, the mattress will quickly unroll and expand. Ensure it is positioned correctly on the bed base and there is enough space for it to fully expand so you don’t need to adjust its position afterwards.


Compressed mattresses may take up to 72 hours to fully expand, so be patient. Avoid placing or stacking items on top of the mattress as this can leave marks, indentations and prevent the mattress from expanding properly. Inspect the mattress regularly to ensure it is expanding as expected, and there are no signs of unevenness or defects.

How to help your mattress expand faster

Allowing your mattress to fully expand before sleeping on it will help ensure it remains comfortable, supportive and in good condition. While this can be frustrating, especially if you’re not sleeping well on the old one, it’s important to remain patient. Fortunately, there are some things you can do that might help accelerate the expansion process so you can sleep on your mattress sooner.

Unpack your mattress as soon as possible

Unpack your new mattress as soon as possible. Leaving it in the box can damage the components and affect its ability to expand.

Applying gentle pressure

Once unrolled, applying gentle pressure on the mattress may help the mattress expand more evenly and rapidly. However, avoid using excessive force, as this can damage the mattress.

Slightly increase the room temperature

Increasing the room temperature slightly may help to soften foam layers and speed up the expansion process.

What happens if the mattress does not fully expand?

Sometimes, a compressed mattress may not fully expand because it’s vacuum-packed a bit tighter. It might need a few extra days to recover fully. If the mattress hasn’t expanded completely after this period, contact the manufacturer or retailer for guidance.

How to take care of your new mattress

Having invested time and money choosing a new mattress, you will want to take proper care of it once it’s fully expanded and ready for use. Here are some practical tips to maintain its condition and extend its lifespan.

Use a mattress protector

A quality mattress protector safeguards your bed from spillages, ensuring a clean, safe, and comfortable sleeping environment. Most protectors fit like a fitted sheet, using elastic straps or a skirt stretching over the corners of the mattress. Encasement-style protectors are also available that zip around the mattress, covering it entirely.

Compressed or rolled-up mattresses often contain foam that closely conforms to body shape. An overly thick mattress protector creates an additional barrier between you and the mattress. Therefore, it is advisable to use a relatively thin mattress cover that protects your mattress without affecting how it feels and performs.

Turn your mattress

All mattresses, whether they contain loose fillings or foam, will settle over time. Turning your mattress helps distribute the fillings evenly. To ensure you are correctly turning the mattress, refer to the manufacturers’ care instructions which are usually provided with the mattress.

Generally, turn your mattress weekly for the first three months and monthly after that. Double-sided mattresses have fillings on both sides and can be flipped and rotated.

Airing your mattress

You may notice a slightly unpleasant smell when unpacking your new mattress. This is perfectly normal, and the smell should dissipate once the mattress has been well-aired. Allow the mattress to air in a well-ventilated room for a few hours, and if necessary, open doors and windows to let in fresh air.

Ensure your mattress is correctly supported

Ensure you place your mattress on a suitable bed base that provides adequate support. Foam mattresses, for instance, typically perform well on firm, flat surfaces, such as platform tops or slats. Ensure your mattress rests on a well-ventilated base that allows good air circulation. Avoid using an old bed base, as this can damage the mattress and invalidate its warranty.

How long does it take to get used to a new mattress?

It takes time to adjust to a new mattress, so don’t be concerned if it feels uncomfortable initially. You may even experience some back pain from the new mattress. However, after a few weeks, the mattress should feel more comfortable as your body adapts to it. 

Final thoughts

While some manufacturers allow you to sleep on a compressed mattress immediately, waiting until it fully expands is advisable. Always refer to the manufacturer’s care instructions before use, which provide specific guidance on how to care for your mattress and get the most out of it. 

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About the author

About the author

Tony Brown is the founder and creator of The Bed Consultant. His career in the bed industry began in 2002. After graduating from university with a degree in Business Administration, Tony joined one of the largest independent furniture retailers in the UK as a bed consultant. Tony has helped thousands of customers find the perfect mattress.

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