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How to Cut a Memory Foam Mattress (Step-by-Step Pictures)

One of the advantages of having a memory foam mattress versus the traditional innerspring mattress is that you can cut a memory foam mattress if you need to.

Do you have a memory foam mattress that you are looking to cut? Maybe you want to alter its size slightly to fit in an antique, 3/4 bed set or RV? Maybe you just want to cut it up and dispose of it? Whatever the reason, in this article we will show you exactly, step-by-step, how to cut a memory foam mattress without ruining it.


Reasons to Cut a Memory Foam Mattress

Cutting a mattress may not seem like something anyone would ever have a reason to do. However, when disposing of the old mattress, some landfills and companies that pick up trash will dispose of them at no extra charge if they are in a trash bag.

Traditional mattresses are almost impossible to cut in a way that they would fit into a trash bag. Most traditional mattresses have metal springs in them. You could cut the fabric away from the springs, but you would still have those springs to dispose of.

To fit a different or custom size bed

If you have an odd size bed like an olympic queen or full xl or want to downsize your mattress but like your current memory foam mattress, cutting the mattress to fit the new frame may be a good option. Traditional innerspring mattresses are not easily able to be cut and downsized. With those mattresses, your only option is to purchase a new mattress.

To repurpose it

One popular trend lately is to reuse items. Upscaling furniture and other things can be seen all over Pinterest and social media. Memory foam mattresses are no exception. Maybe you need a cushion on a bench or chair; your old memory foam mattress may be just what you need.

Memory foam mattresses can range in price from around $100 for a small, thin topper to several thousand dollars. Prices depend on size. King size is usually more expensive than twin size. The brand also has a lot to do with price. Ingredients in the foam also affect the price. So, if you have a memory foam mattress that you like but need a smaller size or want that comfort in a chair cushion, cutting the mattress is a perfect option.

Part 1: Preparing to Cut

Step #1: Check to make sure your mattress does not contain fiberglass (most modern mattresses do not)


The first step in preparing to cut a memory foam mattress is to find out the material that makes up the memory foam. Some mattresses will contain fiberglass. If you were to cut a memory foam mattress containing fiberglass, the fiberglass particles would be released into the air.

Fiberglass particles can be harmful to breathe in. You have probably seen people who install fiberglass insulation put on masks and special suits to do the job. If your mattress has fiberglass particles in it, it is best not to cut it. To find out if that’s the case, you can go to the online description of your mattress or even contact the manufacturer.

Step #2: Unzip/Remove the cover


The next step is to take the covering off the mattress. If you are disposing of the mattress, this may not be as important. However, if you are resizing or reusing the mattress, you may need the cloth cover in its new life.

For mattresses with zippered cover:


Most memory foam mattresses have a zippered fabric cover over them. If so, this part is easy. Simply unzip the cover and take it off of the mattress.

For mattresses with a sewn on cover (2 options):

If your mattress has a sewn on cover instead of a zippered cover this step may be slightly harder.

Option #1 – To get the cover off without damaging it you will want to find the seam where the mattress comes together. At the seam find a portion of the thread holding the seam together and snip it. You should be able to pull the thread and take the seam off (You may need to do this twice if the seam has a top and bottom thread


Option #2 – You can simply find a section (preferably at the head or foot of the mattress) where you will cut the cover with scissors or a knife. Be careful not to damage the mattress. Then simply cut from one end to the other and slide the mattress out from the cover.

Step #3: Cut the fire sock.


Similar to how you cut the cover. Find the fire sock seam at the head or foot of the mattress and cut it from one end to the other. This will allow you to slip the fire sock off and slip it back on afterwards.

If you are disposing of your mattress you can simply rip the fire sock off.

Step #4: Make sure your mattress is on a flat hard surface.


You should lay the mattress out on a firm surface to measure and cut. In most cases, this would be the floor. Whether you are disposing of the mattress or reusing it, having a firm cut surface is very important and will make cutting a lot easier. It is also much safer to cut something the size of a mattress on a firm surface than trying to freestyle the cut while it stands on its side.

Step #5: Measure


We have all heard the adage “measure twice and cut once.” It holds here too as you do not have a backup mattress. Be sure to get an accurate measurement of what the mattress needs to be after cutting.

To measure the mattress, you can use a ruler, a yardstick, or a tape measure. The ruler and yardstick are stiffer, but the tape measure has an end that can hook onto the side of the mattress to stay in place while measuring. 

The important thing is to get an accurate measurement. It may be a good idea to add about a quarter of an inch to your measurement. This allows for minor errors in cutting, measuring, or the width of the cutting tool. Foam is forgiving and can often squeeze into a tight space. You can always trim more off the mattress, but you cannot add back what you cut off. So getting an accurate measurement is vital.

TIP for measuring for disposal

If you are cutting the mattress to dispose of it, then be sure to measure the trash bags so that the pieces fit in easily. 

TIP for measuring when resizing your mattress

If you are downsizing your mattress, be sure to measure the new bed frame accurately. If you are using it as a cushion, you need accurate measurements of the seats or bench that it will be used for.

Step #6: Mark your cut


Once you get the correct measurement, mark the measurement with a sharpie or marker. You should use a ruler or straight edge to draw a line for the length of the part you wish to cut off. Having this line as a guide will make you less likely to cut a crooked line or go off course in cutting. A carpenter’s chalk line would also be a great option.

PART #2: Making the Cut

Now that all the preparedness has been taken care of, you are ready to cut. An important step here is to figure out the best cutting tool.

Step #7: Using the right cutting tool for your job




If the mattress is a smaller size and not very thick, you may be able to use a good pair of sharp scissors. The thicker the mattress is, the less likely scissors will work well. Sharp scissors would probably work great if you are just cutting down a mattress topper. If you are cutting down a thirteen-inch thick mattress, scissors would not work very well.

Utility Knife


A utility knife, the kind with the razor blade, is excellent for making exact cuts. The only problem with using one of those is that you will need to go over each section multiple times, each time cutting deeper and deeper (compressing, or squishing, the mattress will help to get the foam thin enough for the knife to cut through easily. This method can be done, but it takes patience.

Electric knife (electric turkey knife works great)


An electric knife is one of the best tools for cutting a memory foam mattress. Yes, the electric knife that is only used at Thanksgiving now has a new purpose. Because of the blade’s speed, the cut will tend to be smoother and cleaner. Less effort on your part will be needed to pull the knife through the memory foam.

Bread knife


If you do not have an electric knife, you can use a bread knife with a serrated edge. Again, the thickness of the mattress needs to be considered. A very thick mattress will require a longer knife. A thinner mattress, or mattress topper, can be cut with a shorter blade.

Hot wire cutter

Some people may have a hot wire cutter in their tool shed. This tool can be helpful if the memory foam you are cutting is a smaller piece or if the memory foam is dense. However, if you are trying to cut the memory foam into less thick pieces, a hot wire cutter is a perfect tool. For example, if your memory foam mattress is thirteen inches thick and you need a thickness of six inches, a hot wire cutter would be the best tool for the job. BUT NOTE: Cutting a memory foam mattress horizontally to reduce the thickness is tricky. If you want to reuse the mattress as a smaller one, your cuts need to be careful and accurate. When you cut to reduce the thickness, there is a high chance that the cut won’t be even, and the mattress will have varying thicknesses. You don’t want a lumpy bed!

Part #3: After the Cut

Now that you have cut your memory foam mattress, you can proceed with your next steps. If your reason for cutting it down was to dispose of it, then fit the pieces into trash bags and send them off with your weekly trash pickup.

If you cut your mattress down to reuse, your next step should be covering it.

STEP #8: Recovering your mattress


If you are reusing it as a mattress, you can slip back on your previous mattress cover or you can purchase replacement mattress covers or just a mattress protector online. You could just put your sheet over the mattress, but remember there is now a raw edge and foam particles could begin to shed. So, placing a cover over the mattress before the sheet is the best thing to do for preservation.

If your purpose was to reuse the foam as cushions, then now is the time to make your cushion covers. You could also buy cushion covers. The important thing is to get the foam covered. You don’t want to waste all that work to have the foam damaged before you can use it.

Frequently Asked Questions

Now that we’ve covered how to cut a memory foam mattress step by step, here are some of the most frequently asked questions about the process. 

Can I cut my memory foam mattress?

You can cut your memory foam mattress. Whether you need it in smaller pieces or need to reduce the thickness, you can do it with the right tools.

What tools do I need to cut my mattress?

There are a few tools you need to have on hand. A ruler, yardstick, or tape measure is a must-have for measuring accurately. Use a marker to draw a line to cut along to minimize mistakes. You can use sharp scissors or a very sharp knife, but ideally, an electric knife is the tool to use.

What are some things I could do with my mattress after cutting?

You can still use your mattress as a mattress. Cutting your memory foam mattress to resize it is a great option. You can also use the foam as a cushion for chairs and benches. You can also spruce up the cushions on an old couch

Memory Foam Mattresses Today

Memory foam mattresses are very popular with consumers right now. According to Mattress Clarity (Mattress Industry Statistics and Trends), 66% of consumers looking to buy a new mattress are looking at memory foam. Why? There are a few reasons for this.

Memory foam offers a contouring effect. The foam contours to your body to offer support while reducing pressure points. Your spine, knees, and hips may benefit from a memory foam mattress.

Some memory foam even offers cooling features. For people who tend to be warm when they sleep, a memory foam mattress’s cooling effect may help regulate your body temperature and allow you to get a night of better sleep.

There are also memory foam toppers. These are generally one to four inches thick and lay on top of your mattress. They offer some of the same benefits as a mattress without the expense. Memory foam toppers are also easier to maneuver on the bed. They are lighter than a full mattress, making it easier to put one on your mattress without assistance.


Cutting a memory foam mattress is something you can do. Whether you still want to use it as a mattress or are interested in reusing it for other projects, cutting your memory foam mattress can be a great option. Just remember to follow the steps to prepare for the task adequately. 

The most important things are to get an accurate measurement of the new size you need and have sharp cutting tools to do the job. By following the easy steps we discussed here, you can easily cut your memory foam mattress down to a smaller size or even a smaller thickness.

You do not need to be intimidated by this project. Just take your time and remember to measure twice and cut once. You will be able to enjoy your memory foam mattress in many forms for years to come.

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