Also known as: Density kg/m3, Foam GSM
Foam density is the mass of foam per cubic metre, expressed in kg/m³. It is the primary indicator of how much energy a foam can absorb: higher density supports heavier products, while lower density suits light items. Density, not thickness alone, determines cushioning performance.
Density is measured in kilograms per cubic metre (kg/m³) and describes how much polymer is present in a given volume of foam. A 45 kg/m³ EPE contains more than twice the material of an 18 kg/m³ EPE of the same size, and resists compression accordingly.
The engineering relationship that matters is static loading — product weight divided by the foam contact area, usually expressed in grams per square centimetre. Every foam grade has a loading range in which it performs best. Below that range the foam is too stiff and transmits shock straight through; above it the foam bottoms out and the product effectively hits the box wall.
This is why "use thicker foam" is not automatically the right fix. If the density is wrong for the load, adding thickness may not help — and a common failure in practice is a heavy machined part sitting on foam so soft that it compresses fully on the first drop.
The correct approach is to work from product weight, the area of foam actually in contact, the expected drop height for the transport mode, and the fragility the product can tolerate. From those, density and thickness are selected together.
Foam Density at a glance
| Unit | kg/m³ (kilograms per cubic metre) |
|---|---|
| EPE range | 18–45 kg/m³ |
| EVA range | 35–200 kg/m³ |
| PU range | 14–40 kg/m³ |
| EPS range | 10–30 kg/m³ |
| Design inputs | Product weight, contact area, drop height, fragility |
Common questions
What is the typical EPE foam density, EVA foam density and PU foam density for packaging?
EPE foam density for packaging is 18 to 35 kg/m³, with 25 kg/m³ the standard sheet grade. EVA foam density runs 60 to 120 kg/m³ for fitments and tool trays. PU foam density for cushioning is 16 to 40 kg/m³. Higher density gives a firmer foam that carries more load per square centimetre but cushions light products less.
Does higher density foam always protect better?
No. Foam that is too dense for a light product is effectively rigid and transmits the shock straight through. Protection comes from matching density to the static load — product weight spread over the foam contact area — not from maximising density.
How do I calculate the foam density I need?
Start with product weight divided by the foam contact area to get the static loading in g/cm², then choose a grade whose cushion curve is efficient at that loading and at your expected drop height. We do this calculation as part of quoting a fitment.
Need EPE Foam Sheets & Rolls for your product?
We manufacture epe foam sheets & rolls at our Rajkot unit and dispatch across India. Send the product, size or weight and monthly quantity and we specify and quote within one working day.
Or read the full specification: EPE Foam Sheets & Rolls