How To Cut a Foam Mattress: A Detailed Guide!

Are you looking for the best way to cut a mattress? Many times, we want to reuse our old mattress for something but can’t seem to fit it due to varying dimensions.

Most people don’t know how to cut a foam mattress properly and end up ruining it. This ends up happening because they don’t use the right tools.

So, if you want to reuse your old memory foam, then read on to learn about essential tools and the best way to cut the mattress and reuse it accordingly. Let’s dive in!

Can You Cut Up a Memory Foam Mattress?

Yes, it is very easy to cut a mattress if you follow the right steps. There may be several reasons why you would want to cut your old mattress.

If you are someone who wants to reuse the old mattress on a smaller bed or an in a van, then you will need to cut it. You can basically reuse the old mattress without needing to buy a new one.

Cutting a Foam Mattress: Step-by-step Guide

Cutting a mattress is highly dependent on the type of materials it contains. It is because due to the presence of fiberglass or gel, the cutting can become a bit more difficult. We are going to provide you with a step-by-step guide on how you can easily cut an old memory foam mattress at home.

How to cut a foam mattress

Best Knives to Cut an Old Memory Foam Mattress

You don’t need a big tool in order to cut memory foam. It can be cut using a simple knife but the cutting is not very efficient in that way. So, the best thing is to use one of the following items.

Best Knives to Cut an Old Memory Foam Mattress
  • Electric Knife: An electric knife is probably the best way to cut memory foam mattress toppers as it is the easiest way of doing it. No additional force is required while using an electric knife and you only need to push in the direction of the cut.
  • Long Carving Knife: It is also a good choice because a carving knife is long and really sharp. You will need a bit of back-and-forth action but end result will be good.
  • Heavy-Duty Scissors: If you don’t have any big knives then a large scissor will work just fine. Just make sure to use the front part for a cleaner cut.
  • Utility Knife: This sharp knife is good for cutting through a gel memory foam mattress. With its pointy end, you can easily make a cut and then go through with it till you reach the bottom. Don’t saw through the mattress in this case.
  • Bread Knife: Using a bread knife is not a bad choice if it is sharp. In this particular case, sawing motion is necessary to cut through the mattress cover and the material.

Other Necessary Tools

You can easily transform your old memory mattress into a new one with the help of some simple tools. Here are some of the things that you’ll need:

  • Measuring Tape/Rule: For measuring the dimensions
  • Sharpie: For marking the position of the cut
  • Seam Ripper: Only if the mattress cover is not removable
  • Sewing Kit: For sewing up the cover at the end
  • Long Board: In order to make straight cuts

Cutting the Memory Foam Mattress to the Desired Size

Now, you know all of the tools that are required for cutting, it is time to make the cut. Before we start the cutting process, it is necessary to ensure that the mattress doesn’t contain fiberglass.

Cutting the Memory Foam Mattress to the Desired Size

Warning: If your old foam mattress contains fiberglass then you shouldn’t cut into it. This is because it will cause the fiberglass particles to release into the air and these particles can have really bad effects on your health.

When you are sure that there is no fiberglass present, then you start the cutting process. The following steps will allow you to efficiently cut your memory foam mattresses:

Step 1: Take the cover off

The first thing is to take off the mattress cover. There are a lot of memory foam mattresses whose covers you can easily take off. If it is not removable then you should use the seam ripper.

Step 2: Lay the mattress on a solid surface

The best approach is to use plywood beneath the mattress to avoid damaging the floor. In order to prevent the mattress from sliding off, you can also place some heavy things at the corners.

Step 3: Measure out the exact dimensions that you need

Now, is the time to use the measuring tape to map out the dimensions of the memory foam. Mark the dimensions that you need with a sharpie or a pen so that it is easier to cut along it.

Step 4: Start cutting without any compression

You should start to cut the memory foam following the line that you previously marked with the sharpie. Make sure not to compress the mattress as it can ruin the cut. If you have soft memory foam, then use plywood beneath it to avoid compression.

Step 5: Cut off the excess

If the edges are not clean, then you can use a pair of scissors to cut off the excess. This will result in a cleaner mattress.

Step 6: Put it on the cover

After you are done with the cutting and trimming. Now is the time to place your now new mattress in the cover. You can either use a sewing kit or safety pins for securing the mattress in the cover.

You can also follow this video for more detailed instructions.

How to Cut a Memory Foam Mattress Horizontally?

If you want a thin mattress then you need to cut it horizontally. But cutting a foam mattress horizontally is easier said than done. This is because a lot of things can get messed up and you need more precision in your cutting. It also requires some special tools such as:

How to Cut a Memory Foam Mattress Horizontally

Method 1: Use a Horizontal Saw

Using a horizontal saw is the most common way to make long horizontal cuts in the mattress. You should start by holding the top part of the memory foam and then slowly moving the saw through it. A good tip is to use a sheet underneath to catch all of the flying bits.

Method 2: Use an Electric Saw

You can also use an electric saw if you have one but this is a more dangerous method and should be used with caution. A regular saw is a much safer option to cut the foam.

Method 3: Use the Hot Wire

The third method is to use a hot wire. This is a very difficult method and you will need a steady hand for the best cut.

Attention! We don’t recommend cutting the mattress horizontally as you can easily damage it in the process. Furthermore, there is no surety that the mattress will feel the same after the cut. If want to make your mattress thinner, then you will be better off buying a new one instead.


Why cut up my foam mattress?

A lot of people tend to cut memory foam mattresses in order to make them suitable for a smaller bed or to fit in a van. These are some of the common use cases for cutting up a mattress.

Is it possible to cut a foam mattress?

Yes, it is indeed quite possible to cut a mattress. You just need the right tools like an electric knife or a carving knife and you are good to go.

What is the best way to cut a memory foam mattress?

The best way to cut memory foam is by first placing it on a solid surface. Use a tape measure to measure the dimensions and a marker pen for mapping out the cutting area. Use a sharp knife to cut the mattress in a straight line.

What is the best thing to cut foam with?

There are a lot of things that you can use to cut foam mattress. A large knife or a pair of large scissors work best to cut the mattress.

How do you cut a foam mattress with a knife?

Make sure that the old foam mattress is present on a hard surface and just follow the line that you marked with the pen or sharpie. As long as you are not compressing the mattress during the cutting, you will get a good cut.

What is the easiest way to cut up a mattress?

An electric knife is probably the easiest way to cut mattresses. With the knife being electric, you don’t need to exert a lot of force to cut the fabric. Just follow the marked line and you will get a clean cut.

How do you cut foam without a foam cutter?

There are multiple ways to cut a foam fabric. If you have any long knives or large scissors then you can easily do it in your home.

Can you cut a mattress to make it smaller?

It is possible to cut a mattress and make it smaller. In fact, a lot of people do this with their memory foam mattresses and fit them in their cars.

How to cut a foam mattress in half?

Different tools can be used for cutting a mattress in half. You need a sharp item like a long knife or big scissors to get a clean cut.

How to cut a foam mattress thinner?

If you want to cut a memory foam mattress thinner, then you can do that with a horizontal saw. However, it is not advisable to make it thinner as it is very difficult and you might end up ruining the whole mattress.


With the help of a few things, you can easily trim down your old mattress and essentially make it new. It allows getting any size mattress you want. The only thing that you need to be cautious about is compressing the foam. Cut it carefully and you will get an entirely new memory foam mattress that you can use elsewhere.

What are your views about our guide and why are you cutting up your old mattress? Let us know in the comments.

Leave a Comment