Things You'll Need:
- Tape measure
- Ruler or yardstick
- Permanent marker
- Scissors or electric knife
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Step 1
Decide what size mattress topper you need. Mattresses come in standard sizes, so if you don't know what size your mattress is, you can measure it. Few manufacturers still make full-sized beds, so if you have an older mattress, you will need to measure it. Here are the standard sizes:
Twin: 39 inches by 75 inches (99 by 191 cm)
Long Twin: 39 inches by 80 inches (99 by 203 cm)
Full: 54 inches by 75 inches (137 by 191 cm)
Queen: 60 inches by 80 inches (152 by 203 cm)
King: 78 inches by 80 inches (198 x 203 cm)
California King: 72 inches by 84 inches (183 by 214 cm) -
Step 2
Lay the memory foam out on a raised, flat surface, like your kitchen or dining room table. Make sure the edge you are cutting hangs over your table edge, so that you don't damage your table.
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Step 3
Use a permanent marker and a ruler or yardstick to mark the line you need to cut.
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Step 4
Use the electric knife or scissors to cut along the line you have drawn. Stop often to make sure that the foam is straight and that you are following the line correctly.













