To cut a foam mattress, you need multiple tools, including a straight edge, measuring tape, a marker, and an electric cutting knife. Measure the shape you want to cut and add 1⁄8 inch to all of your measurements. Draw out your cutting lines as a guide. When making the cuts hold the knife perpendicular and don't compress the foam at any time.
Custom shapes for spaces
Before you cut your mattress, you should check to see if the shape you want is offered anywhere. Here are a couple of recommendations.
- Foamorder- They offer any shape in multiple different materials.
- MattressInsider- Their website has many different shapes and sizes already laid out for you to look at
- FoamSource- Specializes in RV and travel mattress shapes
If you're looking for a weird shape or are reusing an old mattress, continue reading.
Measuring and marking the foam
- Remove the slipcover if you're cutting a memory foam mattress. If your slipcover doesn't have a zipper, you may have to cut it off to access the mattress. Foam mattresses that are not memory foam typically won't have a slipcover.
- Measure the dimensions you need a second time. Add 1⁄8 in (0.32 cm) to them. Adding the extra 1⁄8 in ensures the size is consistent in case cutting removes some foam. This should ensure your memory foam is cut to size.
- Use a permanent marker and a tape measure to make cutting marks on the foam. Use your straight edge to ensure your cut lines are straight. If the lines are too thick, the marks may still show after cutting.
- Warning: Don't compress the memory foam while measuring or your cuts are going to be inaccurate.
Cutting the foam
- Set the foam on a table, hanging over the edge.
- Tip: A heavy object (like a large book or a suitcase) holds the foam in place if it tips over the edge.
- Use an electric carving knife.
- Alternative: A large kitchen, while nowhere near as simple or clean, can still do the job. The edge might look quite ragged, but that won't matter if you're putting a cover on it.
- Guide the knife along your cutting line you drew on the foam.
- Alternative: If you're using a kitchen knife, saw up and down slowly.
- Cut a second time if you didn't get through the foam.
What to do if you made a mistake
If you make a mistake, don't worry, there are still plenty of options. You can always refer to our earlier list of companies to find the shape you want in their inventory or look at our list of top mattresses in 2023 if you decide to shop for a new bed altogether.
Where can I find a great, affordable mattress (in 2023)?
If you're searching for an affordable mattress that offers a wide range of comfort and pressure relief, we've compiled a list of mattresses for you to consider:
- Saatva Mattress - fantastic for all sleep positions, and is rated our Best Mattress of 2023.
- Puffy - feels like you're sleeping on a cool cloud (at a good price).
- Cocoon - amazing pressure relief at an affordable price.
- Ghostbed - beautiful, plush cover w/ aerated latex and healthy spinal alignment.
- Winkbeds - 3-stage back relief with free shipping and returns.
Read our short, well-researched 10 Best Mattresses of 2023, here. Our ultimate goal is to help you pick your perfect mattress online, today!