How To Cut a Memory Foam Mattress?

Sometimes a comfortable memory foam mattress doesn’t fit in the space you’re trying to put it or you don’t have a good reason to change its size, so you’ll need to cut a memory foam mattress.

The ideal method for cutting a memory foam mattress is to gather your tools and supplies before marking the foam with lines where you wish to cut.

Make precise cuts utilizing a technique that is appropriate for your chosen blade. Trim any extra material or sharp edges after you’re done.

I’ll explore the reasons to cut a memory foam mattress into smaller pieces in this article with the measures you need to do to achieve it.

Is It Safe to Cut a Memory Foam Mattress?

A memory foam mattress can be trimmed without any issues.

Simply knowing how much you want to remove will be necessary if you want to make the cut correctly the first time around without having to deal with spray glue.

There are a variety of reasons why you might wish to modify the size of your memory foam mattress. Some of the motives are as follows:

  • It would be placed on a smaller box spring.
  • To use with a unique base.
  • To adapt to a unique space, such as a mobile home.
  • Dividing a large mattress into two smaller ones.
  • To make use of any extra memory foam for cushioning, pillows, crafts, or other uses.
How To Cut a Memory Foam Mattress

Which Knife Should I Use to Cut Memory Foam Mattress?

The knife you use will affect how clean your cut is and how challenging it is to make the cuts in your memory foam mattress.

Additionally, different blades will require various cutting methods.

Electric Knife:

Electric Knife

These knives are often serrated and very simple to use; they consist of merely two extremely thin edges plus a motor that causes them to vibrate.

For cutting foam, you usually simply need to slide the knife along your cut lines in order to produce very precise cuts.

Carving knife:

Carving knife

Serrated edges are common on carving knives, which resemble electric knives without a motor.

Although the serrated edges cut through foam effectively, they frequently produce jagged cuts that require further clean-up.

For optimal results, move this knife back and forth in extremely brief movements.

Heavy-Duty Large Scissors:

Heavy-Duty Large Scissors

Extra-large or heavy-duty scissors are an excellent choice for cutting thin memory foam mattresses or memory foam mattress toppers, provided that they can fit between the scissor’s jaws.

Cut following your cut line a tiny bit at a time to keep cuts as straight as possible.

Your cut can go off course if you make too many consecutive cuts.

Utility Razor Knife:

Utility Razor Knife

Due to the fact that they actually use a razor blade, utility razor knives are excellent at cutting memory foam.

Compared to a carving knife, these are made separately and have smoother blade edges.

When using a razor knife to cut memory foam, start along the cut line and make further passes to deepen the cut until it is completely through.

Horizontal Saw:

Horizontal Saw: How To Cut a Memory Foam Mattress

Only use this kind of saw if you intend to cut the mattress horizontally.

You must hold the mattress still while making that type of cut without placing any weight on it. If you don’t, it can distort or compress.

Cutting Memory Foam Mattresses:

Cutting Memory Foam Mattresses

It’s time to sketch your intended cuts on your memory foam mattress and actually make them now that you know what knife to use.

Depending on the blade you use, further trimming might be required.

Collect Materials and Tools:

In addition to your memory foam, you’ll need a few other things to make the process as easy and comfortable as possible.

What you’ll need is as follows:

  • Preferred knife
  • As a straight edge, use a square of plywood or drywall.
  • Safety eyewear or goggles
  • Pen or marker for writing
  • Measurement tape
  • Ruler
  • Spray adhesive is necessary if you wish to join components together, although it is optional.

Determine Dimensions and Draw Cutting Lines:

Determine Dimensions and Draw Cutting Lines

Determine the precise proportions you require before beginning to cut. If all you’re doing is splitting the mattress in two, this won’t matter.

However, you should pay great attention if you’re custom-fitting the mattress into a particular space, such as a boat or vehicle.

Measure the dimensions with a tape measure, and then mark the area with a marker where you’ll be making the cut. Knowing what to do will be a lot simpler if you have a clear blueprint.

When doing this, keep in mind to take into account all three dimensions, and highlight any slants you would need to account for in your outline and resulting cut.

To the markings, add 1/8th of an inch (3.17 mm) when measuring. Where you make the cut is in the extra area left over from the material that will be removed and lost when you make the cut.

This additional space is only present to guarantee that your cuts are exact. You might need to draw outlines on both sides when working with memory foam mattresses that are really thick.

This is due to the possibility that cutting from only one side won’t result in an evenly sliced surface.

When cutting a thick memory foam mattress, I would advise cutting roughly midway through on the first side before flipping it to complete the cut.

When performing this step, be careful not to press any weight on the mattress as this could cause your measurements to be off. One incorrect line can cause the entire shape to be incorrect.

Do the Cutting:

Do the Cutting: How To Cut a Memory Foam Mattress

Place your memory foam mattress on a sizable, flat table or a spot that is absolutely level.

Laying something heavy on the side you aren’t cutting will help keep the mattress in place, but make sure it is far enough away from your first incision to prevent it from compressing the foam and affecting your cut.

Cut while holding your knife directly parallel to your initial cutting line. As previously said, various knives will require various approaches.

Never apply pressure when cutting. The foam will deform as a result, throwing off your cut-off. You can use spray adhesive to reattach anything if you make a mistake and need to glue it on.

No matter the knife, you must use the razor knife technique to cut through thick memory foam mattresses.

Make a shallow first cut, followed by several light succeeding cuts.

Flipping the mattress over and making cuts on that side might be necessary, depending on your outline. There could be several foam layers in your mattress, each with a different thickness.

Some mattresses have bottoms that are significantly thicker than tops. If your mattress has thick layers, be aware that it is more challenging to cut through them.

Ironically, because the light layers tend to bend as you cut as they are easier to cut.

Cut Off Extra Material:

Cut Off Extra Material: How To Cut a Memory Foam Mattress

Based on the particular memory foam mattress consistency and the type of knife you used, the edges of your cuts could not be very clean. They may even be a little ragged, but that’s good because cleaning them up isn’t that difficult.

Take some scissors or a razor knife and simply trim the edges to smooth out the cuts.

You may decide not to trim the surplus, particularly if you want to cover the mattress with a cloth cover or mattress protector nonetheless.

Instead, you can keep the extra foam because loose memory foam works well for stuffing pillows.

Also read: How To Ship a Mattress?

FAQ: How To Cut a Memory Foam Mattress?

Q1. How can a foam mattress be cut by yourself?

Make sure you have a measuring device, a marker pen, and a saw blade so you can determine how deeply it cuts.
Where you wish to make a cut, measure, and mark.
On a flat surface, carefully cut the memory foam mattress or mattress topper without compressing it.
Remove any extra material, then (re)fit the mattress cover.

Q2. How can foam be cut without creating a mess?

The hot wire cutter is extremely comparable to the hot knife and has all of its advantages and disadvantages, but is typically much larger.
It can be used to cut and seal foam with precision and to create sculptures.
Styrofoam sheets in large sizes are typically cut using their huge sizes in commercial applications.

Q3. How can foam be cut without using an electric knife?

When cutting through the foam with a serrated knife, you might need to gently saw the foam with the blade.
Even with a blade that is vertically straight, you should still be able to achieve an even edge.
Use a steady, even motion to properly push the wire through the foam if you’re using a hot wire cutter.

Also read: How to Break in a New Mattress?


Memory foam mattresses are incredibly cosy with some forethought and a sharp blade, they can even be made to order.

It is simple to cut a memory foam mattress with just a few straightforward actions and a sharp eye.

Hello & welcome to Homeprettify! I'm Pooja and I have a passion for all things design, decor, and renovation. I am a serial renovator, currently working as Civil Engineer. Look around, leave a comment, and don't forget to subscribe to my emails so you don't miss out!

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