Furniture
Foam Density (ILD/IFD)
Definition
Foam density is measured in pounds per cubic foot (lb/ft³) or kg/m³; higher density (1.8 lb/ft³ / 28 kg/m³+) indicates more durable, supportive foam. ILD (Indentation Load Deflection) measures firmness — the force required to indent the foam 25% of its height.
Why it matters for dupe shopping
Low-density foam (under 1.5 lb/ft³ / 24 kg/m³) breaks down within 2–3 years under regular use. Quality sofa alternatives specify foam density in their product documentation. If a brand cannot provide these specs, it is a red flag.