Understanding the Numbers in the Foam

Whether you’re purchasing a new mattress for your camper-van, roof top tent or just the spare trundle which only sees the light of day when Aunt Berther visits; you will need to consider the Mattress Density you require.

Density doesn’t necessarily mean you will be purchasing a firmer mattress if the number is higher. The numbers you see refer to the quality of the foam as well as the durability and its lifetime.

Foam of a higher density tends to be heavier and feel solid while those with a lower density are lighter therefore easier to move. When looking at heavier foam, the density is of a higher number which also indicates it has been made to last and provide better durability.

Based on this, you would then choose a foam which would suit your purpose based on the density. The next step is to determine whether you need a firm, medium or soft foam.

Above is the simplicity of choosing the foam, read on to learn about the science (boring to some I know) of Foam.


The Science behind those sets of numbers…

So how then you ask is density calculated, well it is a simple maths formula.

Foam Density is a phrase in the industry which refers to the mass of a cubic metre section of a piece of foam. It is measured in kilograms per cubic metre (kg/m3). In simplest terms, you would divide the weight of the foam by its width x height x length (m3). The determined density is then expressed by weight per cubic foot.

But density doesn’t indicate the firmness or the softness of the foam, there’s another method to those numbers. You can have a high-density foam; a heavy and great quality foam but this can also be soft - an overlay is a perfect example of this. This softness or firmness of the foam is calculated using the Indentation Load Deflection (ILD). The ILD determines how much weight is required to ident the product using a system of force to achieve a percentage of compression.

Summing up those pesky numbers, oh we mean the science behind the coding system; a foam weighing in at 23 kilograms per cubic metre which using the ILD to determine the compression rate of 40% of the original height is achieved by applying force of 130 newton’s is then graded as 23-130. Yes, that’s correct bypass the jargon and your result is a medium density and medium feel foam which is great for the guest bed, children’s beds, and the back of lounge chairs.

Have we lost you yet, don’t worry we made it easier to navigate the chaos of numbers and physics and have provided a chart for you to choose the correct foam for the right project.


Choose the right Foam for your Project








Enduro (Best):



Spare Bed and Occasional Use

Guest bed, Lounge backs

Lounge seats, boat  and swag mattresses

Boat mattress, lounge seats, beds

Suitable for:

Children, Adults for occasional usage

Children and Adults

Adults and Children

Adults and Children

Available as:

Mattress Only

Upholstery Foam


Upholstery Foam


Upholstery Foam




Speciality Foam

Density / Formula

Acoustic Foam:




Memory Foam:



Sound deadening shock absorption

To create softness and density to a firm bed.

To create softness and density to a firm bed.

Suitable for

Studios and houses, camera gear and precious equipment



Available as:

Sheet, cut to size

Overlays various bed sizes

Supply to order