The foam density ratings of a mattress measure the weight of the foam per cubic square foot. This translates to the quality of the foam used.
Many people associate foam density with the stiffness or hardness of the foam, but this is not the case. Firmness of the foam is a factor of ILD which we cover next.
Many foams can be of a higher density but still feel soft. When it comes to the most common type of foam used in a mattress, polyfoam, the average foam density you should look for is 1.8 lbs./ft³. Anything less than that will be of lesser quality, and anything more will have increased durability and more suitable for heavier people.
When it comes to memory foam, a density of 4 lbs./ft³ is the average. Keep in mind that when you increase in foam density, the foam will be heavier, and the mattress will most likely be more expensive, but it will last longer and break down less over time.
