Memory foam mattresses are offered for sale with limited size options. If a memory foam mattress is too big, you can cut it down to size. Boats, campers and custom bed frames often need a mattress in an odd size. Custom-sized memory foam mattresses can be ordered, but they cost several thousand dollars to purchase.

Step 1
Lay the memory foam mattress flat on the ground.
Step 2
Measure the size that you want to cut your mattress. Use a measuring tape to make the measurements and a black marker to mark the measurements. Mark the measurements every few inches on the mattress. So if you want to cut the mattress 2 inches smaller, measure 2 inches in from the edges all around the mattress and periodically draw a dot to mark the measurement.
Step 3
Connect the dots of the measurement dot marks that you made. Use a measuring tape to line up the dots and a marker to draw a line from dot to dot.
Step 4
Cut the memory foam mattress along the lines that you have drawn. Use an electric carving knife to make the cuts. Although scissors or a regular knife could be used to make the cuts, an electric carving knife will work better. The electric carving knife will make a much smoother cut. Pay attention to the position of your knife. Hold the knife straight, in an up and down direction, so that you get a straight cut on both sides of the mattress.
Step 5
Pick up the scrap pieces of memory foam that you cut off the mattress. Do not leave the scrap cuttings on the ground, as they are a chocking hazard for small children and pets. Either throw the scrap pieces away in the trash can or save the scraps for future craft projects.
Skill: Moderate
Ingredients:
- Measuring tape
- Black marker
- Electric carving knife
Tip: Practice cutting with an electric carving knife on a scrap piece of material so that you can get a feel for how the knife cuts before you start cutting the mattress.
Warning: This project should only be done by an adult.
Keyword: Memory Foam mattress, cut a memory foam mattress, home decor, electric carving knife
