How To Cut A Memory Foam Mattress

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Have you ever been in a situation that got you wondering how to cut a memory foam mattress? You know those times, your bed just seems too big for the purpose you want it. Well, I am glad to tell you that you will learn the process right here.  The steps that will be discussed here have proven to be effective and are very simple to understand.

Get Your Supplies

electric knife to cut a memory foam mattress

Before we learn how to cut a memory foam mattress, we need to list the supplies needed to perform this operation. The materials required are:

Razor: Different types of razors can be suitable to execute the cutting of your memory foam mattress. The ones I recommend are

Electric knife

  • Electric knife
  • Utility knife
  • Extra-large scissors
  • Carving knife
  • Long serrated bread knife
  1. Measuring Tape
  2. Piece of plywood or hardboard
  3. Marker

Step-by-step Guide to Cutting A Memory Foam Mattress

A memory foam mattress is made with a kind of foam that molds around one’s body (1). This design is significant in the efficiency of the best memory foam mattresses to increase the comfort of individuals in bed. You can cut a memory foam mattress horizontally or reduce the length/width to fit what you want. Now let’s get into the nitty-gritty of cutting a memory foam mattress.

Quote Box

Due to the design of the memory foam mattress that makes it quickly conform to external pressure, make sure the foam is not compressed while measuring, marking, or cutting the memory foam mattress.

Step 1

The first step is to remove the covering of your memory foam mattress. We are trying to cut the foam itself and not the accessories. Therefore, try finding a hidden zip in your mattress cover or get a seam opener to remove the mattress cover. If both options are not available, you will need to cut the cover open (cut the mattress cover at the side if you want to reuse it). Read about the best mattresses in Australia.

Step 2

how to measure out the new dimensions

The next step is to measure out the new dimensions you want the new foam to take. Make sure to add at least 1/8 inch to the new dimensions to give room for error.

Step 3

With the aid of a marker and a measuring tape, mark out the dimensions you have from step 2 on the mattress. Make the first measurement along the edge of the foam. Extend the measuring tape till you get to the desired height and mark the spot with your marker. Move 5 or 10 inches (depending on how wide your mattress is) to the left or right (depending on which side you started from) and repeat the process. Keep in mind the dimensions you want to cut your memory foam mattress.

Also read: Standard Mattress Sizes in Australia

Step 4

Join the marks made in step 3 on the foam so that the cut lines are now visible. Don’t make the lines you draw thick so that there will be little margin for error. If you are making a curved line, use objects that can help with the accuracy of the curve.

Step 5

Put your foam mattress on a platform such that the part you are about to cut is hanging out. You can set a heavy object on the piece of the foam on the platform you placed it on. Ensure the thing is at least five inches from where you are cutting not to compress the foam.

Step 6

Use your razor to cut through the memory foam mattress. Make sure you use the razor to trace the cut lines as perfectly as possible. Start from the edge and cut through to the other side. Also, if the cutting becomes tedious from one side, you can start again from the other edge and meet at the center.

If you find it hard to keep a straight line, use plywood or hardwood to guide the cutline and aid the knife from straying off course. Ensure you are not compressing the part of the memory foam you are cutting to avoid crooked lines.

Step 7

After you cut a memory foam mattress, the next thing is to look for rough edges from the cut surface and try to even it out. Make sure not to get carried away as you smoothen the edges.

Trying to cut a memory foam mattress horizontally (making your mattress thinner) is a bit harder. It will take more time, more patience, and more energy. It is better to use a horizontal saw for this to avoid accidents. 


Can I use giant scissors to cut my memory foam mattress?

Yes, you can, but it will take longer than using an electric knife. While electric knives can get the job done quickly, you should be careful when using them to avoid accidents.

Can I cut my memory foam mattress horizontally in half?

Yes, you can. However, make sure you want to go through with it because cutting mattresses horizontally is hard work, and the results are not usually desirable.


Now that you have learned how to cut a memory foam mattress into a custom-made size, you can convert your memory foam mattress into whatever size you want. You don’t have to throw away your old or too large memory foam mattresses again, and you can simply cut them to function the way you want.

Have you ever cut your memory foam mattress? What dimensions did you cut it? Feel free to tell us in the comments.


  1. Memory foam. (February 2016). NASA Spinoff. Retrieved from

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How To Cut A Memory Foam Mattress

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