If you are into DIY-ing a bench/sofa for your home, you need to purchase a foam sheet first because that will be inside the cushion. If you do not want a cushion, that is an entirely different issue. But the point of concern here is foam cushion and how to cut the foam precisely.

You need to purchase the right foam, meaning the one with exact measurements as your bench seat. You can get your hands-on foam sheets at almost any departmental store. If you want more options and customizations, you can browse the stuff online too.

If you are purchasing them online, make sure of the quality and read the product description thoroughly. If you bought a foam sheet that has different dimensions, it is a waste of money. Luckily if the sheet is more significant than the actual dimensions, you can chop the extras out. But sometimes, even if you buy the right sheet, the edges should be cut according to your bench seat’s shape.

If your bench sheet needs a round-edged cushion, you need to make those edges round. Usually, the foam sheets are 4-inch thick, and you might be wondering how to cut a foam sheet of 4-inch depth?


The first thing you need to go after getting your foam sheet is to mark the sheet. You lay the foam on the bench seat or measure the bench seat to mark the sheet’s dimensions. After measuring the accurate dimensions, take a look at the curved edges’ angle or how sharp the boundaries are.

Your entire cutting depends on this phase because if there is a slight mistake in markings, you will end up with an irregular shaped foam that you cannot use. It is okay to leave half-inch marks as more left out pieces can be cut later, but you cannot add more after cutting them out.

This kind of situation is why you need to be careful and treat markings as a significant 50% part. Many messes the markings up and end up with smaller or bigger cushions.

The Tools

Of course, you need a sharp object to cut the sheet. 4-inches is a firm thickness and might not be easy to cut with a kitchen knife. A typical knife can still cut the sheet but not as precisely as one would want.

It becomes irregular because of the rush and effort you make to cut those edges. You do not want to end up with a badly cut cushion and act like it is alright. It would help if you had sharp tools, sharper, and broader than ordinary knives. You need something that carves!

The Meat Carving Knife!

Meat carving knives are more significant in height and are broader and sharper than regular blades. If you are a meat-eater, you probably have that in your kitchen. You did not know that you could use it, but it works like a charm to cut thick things like a foam sheet.

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A meat carver can easily pierce the foam and cut it like butter. But for the shape, you need to note down the shape and curves of the bench. Mark the curves exactly on the sheet and slowly use the carving knife around the curved markings to make a perfect curve.

If you bought a large-sized sheet, you could still use the meat carver to cut the extra foam to the size you need. For the cut to be precise, use accurate markings because you might just cut more or less than required over sharpness.

Electric Knife!

Now, this knife makes your job even more relaxed and comfortable. Similarly, you must mark your foam for accurate cuts. After the marking, all you must do is to turn the button on! And ride the electric knife steadily along with the markings.

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 As you do not control the speed, the knife is difficult to handle if you have butterfingers. It would help if you had steady hands for the perfect shape. If you are still wondering how to cut foam with an electric knife, there are many videos on YouTube cutting various forms of diverse thicknesses.

The videos exist for a different aesthetic purpose, but once taking a glance at them will give you a good idea of the blade’s positioning. The best suggestion is to use your kneecap or thighs as support for your elbow while cutting. It makes things easy, and your sheet does not go out of shape.

Electric Carving Knife!

Using this beast is also an oddly satisfying job to do! It gives pleasure cutting foam using this. Ordinary meat carvers cannot cut hard meat like turkey and beef, hence electric carvers. 

They are huge and look like mini chainsaws. These are too big to hold, and that weight gives you a perfect steady hold. If you can get hold of an electric carving knife, then this is what you need to make a precise cut. 

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It is heavy, steady, and cuts the foam as soon as it touches the sheet. Of course, the massive structure might make it challenging to move according to the markings. But if you have a company and the other person holds the sheet and helps you move along the markings, this is a great option to cut the sheet precisely as you want. Be it four or even 8-inch, and it can be cut easily with no effort at all.


You need to take the support of something, like a base to the foam. The most logical thing to do is dismantle your seat and use it as support for the foam. If you use the very seat as support, you can cut the cushion precisely with no corrections.

It would help if you cut along the border of this seat. This way is the most optimal solution and reduces the job a lot of times. If you cannot dismantle the base, you can lie the foam down on the seat and use the seat’s outer edge as support and border.

After you are done with one side, you turn the foam around and check the measurements. Put the electric knife/ meat knife on the edges and cut out the extras. Now the cushion is ready and perfectly cut.

Wrap Up

If you are up to DIY-ing your stuff, it is common and helpful to buy yourself the tools you need to DIY. If the reason for self-making is to save, even then, you do not need to worry about the cost. The tools cost significantly less than the product you buy readymade. 

Hence, it is okay to purchase tools, and it is the minimum investment you make to DIY beautiful things. You might have a meat carver, but you might have liked the electric alternatives. They not only clear the doubt of how to cut foam but have many other applications. 

You can cut anything thick and deep using electric knives and carvers. It is good to invest in some tools that are a one-time investment but save a lot of money in the future. It is good to improve your DIY skills and be independent of all the corporate readymade things. 

There is also nothing better than the satisfaction of making your things yourself. It is good to invest money in the tools, and if you are to purchase electric carvers/ knives, it is the right choice as the work you need to do is reduced and different from any other.

Amelia Murphy

Amelia Murphy, with a Bachelor’s in Education from the University of Washington, has been an expert in instructional design and "how-to" content creation for 8 years. She became part of our platform as a freelancer in 2020, offering clear, step-by-step guides on a wide range of topics. Her background includes working in instructional design and as a freelance writer for many famous blogging platforms. Amelia’s previous experience includes teaching and developing educational materials. She enjoys hiking and is actively involved in community literacy programs.

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