Memory foam mattresses have a top layer of memory foam 2” to 5” thick and a base layer 4” to 9” thick. Many memory foam beds also have a quilted pillow top layer made with super soft foam or Dacron fibers. This pillow top layer adds even more softness to the memory foam layer.

A memory foam mattress topper is just the memory foam layer. Some come with a zip off cover, and some without, and some have a permanent quilted fabric cover. A cover is handy for keeping the topper clean, but some allow it to slip around on top of the mattress. Foam toppers without any cover have a lot of friction and don’t slip around. You can keep bare toppers clean by putting them under the fitted sheet. Also you can put a mattress pad or mattress protector over them.

Memory foam beds are a complete package with a body forming comfort memory foam layer and deep support base layers. Foam toppers give body contouring comfort and initial support. They can be used with either a firm foam or innerspring bed. You don’t want to use a topper with a bed that is too soft or slumps in the middle.

When a topper is used on a mattress lacking proper support, it is almost useless. Yes it will be soft and conform to you body, but your hips and shoulders will sink too far into the mattress causing discomfort.