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How To Cut A Foam Mattress? 4 Steps To Follow

Bought yourself a nice and comfy foam mattress and then realized it’s bigger than your bed? You must be quite infuriated. But instead of crying in frustration, you could cut the foam according to your required size. 

How to cut a foam mattress?

First, place the foam mattress in a comfortable position. Then determine the dimensions you want for your mattress. After that, you need to cut the mattress accordingly. And finally, cover the new mattress with fabrics.

Still confused? We’ve got a stepwise procedure awaiting you. Read along to know the details! 

What Kinds Of Knives Are Good To Cut Foam Mattresses?

Before you cut the mattresses, you need to know about the right tool for cutting. You won’t need any heavy-duty equipment. A knife would suffice, but not just any knife. 

The following are the most preferable tools to cut foam mattresses-

Electric Knife

This is probably the most straightforward tool to use. You won’t have to exert much effort because an electric knife will just glide through the foam. Utilizing an electric knife produces the sharpest, cleanest edges.

Here are some of our suggestions, in case you decide to use an electric knife-

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These are the ones that you can use in various tasks. These are quite effective and long-lasting!

Carving Knife

A long, sharp-cutting knife is another top choice for cutting a mattress. To cut through the foam with this knife, you must use to and fro motions. 

You might wonder how weird it is to cut foam mattresses with a carving knife? Cutting foam mattresses with this knife is similar to jigsaw cutting ductwork.

Large Scissors

If you don’t have a proper knife, heavy-duty scissors will suffice. Cut the foam into little pieces. Also, for a cleaner finish, only use the tip of the scissors.

Serrated Bread Knife

A bread knife, if sharp enough, may readily cut through memory foam. To cut through the material, you’ll have to employ sawing motions. 

These are the knives, preferable for cutting foam mattresses!

How To Cut A Foam Mattress? 4 Simple Steps

After getting ready with the tools, let’s get into the real work. Before starting, let’s make you cautious. Make sure your memory foam mattress doesn’t have any fiberglass. 

If it does, the fiberglass particles will be ejected into the room as you begin cutting. And this can have extremely negative repercussions. If you discover that your mattress contains fiberglass, cutting it is not an option. 

Now, the steps to cut a foam mattress is discussed below-

Step 1: Place The Mattress On A Suitable Surface

Begin by removing the mattress cover. Use the seam ripper to open up your mattress if it isn’t removable. Then, using a sheet of plywood underneath, position your mattress on a sturdy platform. 

This will protect your floor from being damaged if your knife collides with it. The mattress might be thin and light. In that case, you might want to put any object at the edges to keep it in place. 

They don’t have to be very bulky. But make sure they’re big enough to keep the mattress from sliding off the bed.

Step 2: Determine The Size You Desire For Your Mattress

You might not be sure about the calculation of it. Calculating this dimension is quite easy unlike calculating a two-person shower dimension. You can do this using any simple measuring tape.

Now, you need to fix the size of the mattress you want. Start measuring as per your calculation, and note it down. Then, using a sharpie or a marker pen, draw the lines according to the revised dimensions. 

Step 3: Cut The Mattress According To The Measurement

Now, you need to cut the mattress according to your measurements. Remember that the foam may have a larger density at the bottom. This implies you’ll have to put in a little more work when you get there. 

When working with softer foams, a drywall square or shiplap is preferable to minimize warping the mattress. If you like, you can alternatively use a piece of plywood. 

Step 4: Cover The New Mattress

Now, you need to cover the mattress that you’ve cut. You should use fabric to cover your new mattress. And that’s when your sewing gear will be useful. You may use safety pins as well if you don’t want to sew. 

You can simply fold the excess fabric and secure the cover. Then pin everything together. But be careful not to puncture the foam.

These are the necessary steps to go through while cutting a foam mattress properly.

What To Do For Cutting The Foam Mattress Horizontally?

You might have to make your foam mattress thinner. In this situation, cutting it horizontally would be a good option. But keep one thing in mind! It can be tough to cut a foam mattress horizontally. 

For this, a long, horizontal saw is a quite common one to use. While cutting, keep the top piece of the foam in your hands. 

But don’t put too much pressure on it when sliding the saw through the material. 

Remember that we always recommend you seek help from the experts for any horizontal cuts. Because one wrong move while cutting the foam mattress horizontally can damage it all.

These are the steps to cut a foam mattress. Go through the steps accordingly to cut into the perfect one!

In case, you are having a hard time moving your king-size mattress upstairs. You can fold it, rope it or even split it to solve the problem.


Question: What could be the best tools for cutting foam mattresses?

Answer: To cut foam mattresses, you could use a variety of instruments. To cut upholstery foam, though, all you need is a serrated knife. It should be on the larger side. And having one at home is fairly common. A simple bread knife will do the trick! This offset bread knife is excellent. But you still might not have got one. You can buy it anywhere and it only costs approximately $11.

Question: Is it okay to use a jigsaw for cutting foam?

Answer: The jigsaw blade S 155/W is designed to cut stiff foam and fiberglass insulation. You can also cut up to 5 inches of foam, cardboard, and other comparable materials. Jigsaw blades from Festool are designed for maximum cutting efficiency, long life, and exceptional cutting results. Most professional jigsaws can use these since they feature a universal T-shank design.

Question: How to cut egg crate foam?

Answer: The first option to cut this is a bread knife or serrated carving knife. Cutting foam is quite similar to cutting bread. It’s only natural that you will use identical knives. Make smooth cutting motions into the foam using a typical serrated blade. 

The Final Words

Now you know how to cut a foam mattress! We believe the information is quite simple. 

We hope you like and find our instructions easy enough.

Best wishes!