Quick answer: Styrofoam is a trademarked brand of extruded polystyrene (XPS), not a generic name. EPS (expanded polystyrene) is made by expanding beads in a mould, while Styrofoam/XPS is made by extrusion. They are both polystyrene foams, but they have different structures, strengths and applications.

The short answer

People use “Styrofoam” to mean any white foam, but that is not accurate. Styrofoam is a registered brand name owned by DuPont (originally Dow), and it refers specifically to extruded polystyrene (XPS). Most of the white foam in packaging, cups and boxes is actually EPS — expanded polystyrene.

How the two are made

EPS — expanded polystyrene

EPS starts as expandable polystyrene beads. The beads are pre-expanded with steam, matured, then fused inside a mould. The result is a mass of bonded beads with a slightly textured surface.

XPS / Styrofoam — extruded polystyrene

XPS is made by extruding molten polystyrene through a die with a blowing agent. It forms a continuous, closed-cell board with a smoother skin and a more uniform internal structure.

Side-by-side comparison

Where each is used

EPS

Protective packaging, appliance and electronics packaging, fish boxes, cold-chain boxes, seed trays, insulation blocks, ICF forms and lightweight fill. EPS dominates because it is cheap, light and easy to mould into any shape — see EPS molds and EPS packaging molds.

XPS / Styrofoam

Rigid insulation boards, flotation, and some craft and model applications. Where a builder needs a thin, high-R-value board, XPS is often chosen.

Which is better?

Neither is universally better. EPS wins on cost per unit of insulation and on shapability; XPS wins on R-value per inch and moisture resistance in a smooth board. For insulation, the comparison is usually made on cost per R-value — see EPS vs XPS for exterior wall insulation.

And if you need repeated impact resistance rather than insulation, neither is the answer — that is where EPP comes in.

Frequently asked questions

Is Styrofoam the same as EPS?

No. Styrofoam is a brand of extruded polystyrene (XPS). EPS is expanded polystyrene. Both are polystyrene foams, but they are made by different processes and used for different purposes.

Is a foam coffee cup Styrofoam or EPS?

Most foam cups are EPS, not true Styrofoam. Styrofoam brand products are typically rigid insulation boards rather than cups.

Which is stronger, EPS or XPS?

XPS boards are generally smoother and slightly stronger in compression, while EPS is easier to mould into complex shapes. The right choice depends on the application.

Are EPS and Styrofoam recyclable?

Both carry resin code 6 and are technically recyclable. Recovery rates depend on local collection infrastructure.

Related products and guides

• EPS Mold Manufacturer
• EPS vs XPS Insulation Analysis
• EPS Packaging Molds
• EPP Mold Manufacturer