Can You Cut a Memory Foam Mattress?

Once in a while, we end up with old memory foam mattresses and wonder what to do with them. Do you throw them away? That wouldn’t be a good idea. Do you reuse them? That’s better but it will depend on how creative you get.

There are a number of things you can do, including cutting them into smaller pieces for reuse.

Can You Cut a Memory Foam Mattress?

It is possible to cut memory foam mattress into an appropriate size for your desired purpose. To cut a memory foam, you will need cutting tools, a marking pen, a tape measure and a supportive surface. Remember that not all mattresses are easy to cut, especially those that contain additional materials such as gel and fiberglass.

Any person, even without much skill can easily cut memory foam at home as long as you have a few tools for the job.

So, let’s see how to trim your foam mattress create pieces that you can use to design something else. But first, let us consider what type of knife can cut memory foam.

So, you’ve finally had a new mattress and don’t want to throw the old one away.

You will need a few more tools to assist you in cutting it into something new, for instance, an RV mattress or cushion for outdoor seats. 

You will need the following:

  • a ruler or a measuring tape
  • a sharpie (to draw the lines that you’ll cut your foam mattress along);
  • a seam ripper (for those with memory foam mattresses that have covers);
  • a sewing kit (it case you want to resize the mattress cover);
  • a drywall square or a plywood/hardboard piece (these are meant to help you cut the foam mattress in a straight line).

How to Cut Memory Foam Mattress

1. Remove the Mattress Cover.

Rip off the mattress cover using a seam ripper if the cover is not removable. You should not begin cutting the mattress when the cover is still intact.

Remove mattress cover before cutting memory foam

2. Place the Memory Foam Mattress on a Firm Surface.

Ensure you protect your floor by putting a piece of plywood below the mattress.

This will prevent damage if your knife slips through. If your mattress is thin and light, consider securing it in place by placing something with weight on the corners, for instance, a few books.

The weight doesn’t have to be too much but you only need it to stop the mattress from sliding around.

3. Check and mark up the dimensions you will need.

You need to determine the size and thickness of the memory foam before beginning to cut it.

Tools for cutting memory foam mattress

The intended purpose will determine the mattress size you mark for cutting. If you’re trying to put your mattress onto a boat, for example, you can’t cut it too tall.

A good long ruler like this one is preferable.

Can You cut a Memory Foam Mattress

Pick up your tape measure or ruler and double-check the dimensions you intend to cut. This will include width, depth, and height.

Once you’ve double-checked the dimensions, add roughly 1/8 inches and put a mark.

Draw a cut line where your knife or saw will cut. Since cutting memory foam removes some part of the foam, the extra 1/8 inch acts as a good buffer.

If you want to cut it into two equal parts, simplify stretch the ruler or tape measure on the side and calculate the center line.

Do not compress your memory foam as you take measurements because it will lead to errors.

Memory foam flattens quite easily. Therefore, it’s advisable to use a medium-density overlay over a high-density mattress.

This will allow you to keep it from collapsing entirely when flattened while remaining comfortable. Fortunately, many manufactures today make memory foam mattresses with this in mind, so expect to find many layers of memory foam.

Fortunately, many manufactures today make memory foam mattresses with this in mind.

So, expect to find many layers of memory foam.

4. Make a Straight Vertical Side-Mark

Once you’ve identified the center of the mattress, the next step is to draw vertical lines on the side.

The side mark should be a straight vertical line to the base of the mattress.

5. Cut the Mattress along Measured Lines

Here, you can use a regular kitchen knife to cut. It doesn’t have to be serrated.

What Knife Can You Use to Cut a Memory Foam Mattress?

When talking about memory foam, you need to remember that it is very pliable, meaning it is easy to cut into new shapes.  As a result, you won’t require any heavy-duty, industrial equipment. A knife is okay to do the job, but not just any random knife picked on the street. The following are some of the best knives to use when cutting memory foam.

  • Electric knives. Electric knives are the most preferred option when cutting memory foam because they are easy to use  All you need to do is to slide the knife through the mattress   Furthermore, when you use an electric knife, you will produce the sharpest, cleanest edges.
  • Carving Knives. Also useful for cutting memory foam are long, sharp curving knives. To cut through the foam with these knives, you will use short back and forth motions to generate accurate slicing.
  • Craft Knives. These knives are usually sharp enough to cut through foam. Plus, they generally have a sharp tip that makes it easy to slice wider foams. However, when cutting with them it is important to should avoid sawing motions. Instead, start by making a shallow cut on one section of foam and progressively deepen the cut up to the bottom and through it. 
  • Extra-large scissors. You may also cut foam mattress using heavy-duty scissors if you don’t have recommended knives. If you want to obtain a cleaner cut and finish, only cut smaller portions of your mattress using the tip of the scissors.
  • Long-serrated bread knife. Yes, you can cut memory foam with a sharp bread knife too. To cut through it, you’ll have to perform sawing motions. The only problem is that the edges of the mattress may come out a bit rugged, but it shouldn’t bother you if you intend to use a mattress cover.  
how to cut memory foam mattress

The goal is usually to end up with clean straight edges after cutting memory foam. 

Therefore, place the mattress on a level surface, with the side you’re cutting hanging over the edge. Avoid compressing the cut line as you cut and that is why a sturdy surface is necessary.

READ ALSO: 6 Steps to Move a Memory Foam Mattress Easily

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Add a heavy object over the mattress. This will keep it in place and ensure that you cut along the pre-marked lines. 

Hold your cutting tool perpendicular to the foam and make a straight cut along the outline you made earlier.

Your blade should follow the cut learn you marked earlier.

If you don’t have access to an electric carving knife, using a bread knife to cut the memory foam is just okay.

Remember: Avoid applying pressure on the cut line. If your knife is too short to cut all the way through, begin by making a shallow cut. Proceed to deepen the cut until it goes through the foam.

If the mattress is too thick, you might have to flip it over and make an outline on that other side. Make sure the measurements are the same on either sides. 

Since the bottom of the foam may be a little harder than the remainder of the memory foam, it may be less difficult to cut. It is much simpler to cut through the harder part than the softer zones because hard sections of the foam warp as you cut.

6. Trim off Excess Material

After you’ve cut out the shapes you want, make sure to clip away any extra material. It’s not necessary to worry about how its edges look if you’re covering it with a mattress cover. 

You have two options for the mattress cover:

  • Re-stitch the old one 
  • Buy a new mattress cover.

This takes us to the next step.

7. Cover the New Resized Memory Foam

This last stage is where having a sewing kit comes in handy. If you don’t want to sew, safety pins will also make a good option. Simply tighten that old cover close against the memory foam, fold the extra fabric, and pin it all together.

How to Cut a Memory Foam with Hot Wire

  • To cut memory foam using a hot wire, you’ll need a bow-cutter like this one here. This is usually great when you don’t want to make a mess.
  • A bow cutter has a wire that gets heater electrically to make a cut through the foam.
How to cut memory foam using hot wire
  • Connect the power source. Use the regular 120 volts that goes into the transformer that heats the wire.
  • After heating the wire, move it slowly along your pre-marked cutting lines to obtain your preferred shapes.

Keep in mind that this method requires an extra steady hand. Also, it might be more convenient for you to cut the mattress if you place it on a taller base.