How Long Does It Take a Memory Foam Mattress to Expand?

One of the first things you need to do when you get your new memory foam mattress home is leave it to expand to full size, which, frustratingly, can take a bit of time.

It can be a bugbear, especially if you’ve already ditched your old mattress. Unfortunately, expanding a memory foam mattress can take up to 72 hours, depending on the size and density, so you may have to spend a few nights sleeping on the couch.

However, it’s worth the wait because once your mattress reaches full size, it will be primed for optimal comfort.

In this informative article, we will answer the question of how long it takes for your memory foam mattress to expand and offer some handy tips to get the most out of your new mattress.

Why Do Memory Foam Mattresses Need to Expand?

Memory foam mattresses need to expand for between 24 and 72 hours. It will allow the foam to activate its unique properties.

When memory foam is compressed and rolled for shipping, it becomes compacted and needs time to regain its original shape and size.

The foam cells open up during the expansion process, allowing air to flow and the foam to breathe. Expanding allows the foam to release any residual odors from the manufacturing process.

So, giving your memory foam mattress time to expand ensures you can enjoy its full benefits for a good night’s sleep.

Tips for Expanding Your Memory Foam Mattress

Tips for Expanding Your Memory Foam Mattress

You can try a few things to speed up the process of expanding your mattress. However, leaving it for the instructed time is vital to ensure you get the most out of it.

1. Follow the Guidelines

While some memory foam mattresses can be expanded and ready for use in as little as 4 hours, meaning you can sleep on it the same night, this could hinder the comfort quality of it, and it might not feel very relaxing.

Another reason to leave your mattress to expand for as long as possible is to mitigate the unpleasant odor that can occur due to manufacturing and packing.

2. Find Space

Find Space

While it might not be convenient, or even possible in some cases, the best way to expand your memory foam mattress would be to lie it flat on the ground. However, it can be expanded on the bed if you don’t have the space.

3. Temperature

Because memory foam is heat sensitive, it will expand to full size quicker at a warm temperature.

4. Roll on It

Roll on It

It may sound peculiar, but you can speed up the time it takes for your mattress to expand by lying it on the floor and rolling on it. Rolling will help to release any compacted air and loosen the foam. Use your entire body weight to do this, and not your hands and feet.

What if Your Memory Foam Mattress Won’t Fully Expand?

In some instances, problems can occur, resulting in the mattress not expanding correctly. There’s usually a valid reason for this and steps you can follow to fix the issue.

  • Be Patient – Your mattress may not expand as it should because you haven’t given it enough time. Try leaving it for another day or two and see if this helps. 
  • Unpack immediately – If you’ve left your mattress in the box for too long, it could hinder the chances of it ever expanding correctly due to being compressed for too long. 
  • Turn up the Heat – If your room is particularly cold, the memory foam may take longer to expand. As the material is heat reactive, turning the temperature to around 20 degrees could solve the problem.
  • Roll on It – Using your body weight to roll on the mattress could give it a boost, especially around the edges. 
  • Speak to The Manufacturer – If you’ve tried all of the above and nothing is working, your mattress could be faulty, contact the manufacturer and check the warranty.


How Long Does it Take For a Memory Foam Mattress to Expand Fully?

The time for a memory foam mattress to expand fully can vary, but generally, it takes around 24 to 72 hours. Refer to the manufacturer’s guidelines for specific recommendations.

Can I Sleep on a Memory Foam Mattress While It’s Expanding?

Waiting until the memory foam mattress has fully expanded before sleeping on it is recommended. It allows the foam to regain shape and provide optimal comfort and support.

What Should I Do if My Memory Foam Mattress Is Not Expanding Evenly?

If you notice uneven expansion, gently pat or roll on the areas that need more expansion time. Additionally, ensure the mattress is placed on a flat, supportive surface to aid the expansion process.

Why Does My Memory Foam Mattress Smell?

It’s common for memory foam mattresses to have a slight odor when expanding. This odor is temporary and is caused by the manufacturing process. Allowing the mattress to develop and air out in a well-ventilated room fully can help dissipate the smell faster.

The Outcome

We understand you probably want to get straight into bed and experience your new memory foam mattress on the first night. However, waiting for the entire expansion time between 24 and 72 hours is highly recommended else could be detrimental to your sleep quality.

Investing in more reliable brands like Tempur-Pedic can determine how well your mattress will expand.

The outcome here is patience is key, and trust us when we say it’ll be well worth the wait.

Sarah Wagner

I'm Sarah Wagner, and I founded Sweet Island Dreams in 2022. It's a blog dedicated to helping people mental vacation virtually anytime they want. By providing information about the best sleep of your life, I help people drift away to paradise without ever having to leave their bed!