What is Foam density?
Foam density (kg/m³)
How much material is in the foam.
Short answer
Memory foam under 40 kg/m³ or PU base foam under 32 kg/m³ is a short-life mattress.
Foam density when buying a mattress
How much material is in the foam.
Why it matters: Low-density foam sags into a body-shaped hollow within two years.
Look for: Memory foam under 40 kg/m³ or PU base foam under 32 kg/m³ is a short-life mattress.
Full Mattress buying guide