upholstery foam grades

Understanding upholstery foam grades is the fastest way to make a reupholstered sofa, bench, or dining chair feel as good as it looks. The right foam keeps its shape for years, while the wrong one flattens quickly and leaves even beautiful fabric sagging. Two measurements do most of the work: density and firmness.

What Foam Grades Actually Measure

Foam Density

Density is the weight of foam per cubic foot, and it is the best indicator of durability. Higher-density upholstery foam generally resists breakdown longer, making it the smart choice for seats that see daily use.

ILD Firmness Rating

The ILD (indentation load deflection) rating describes how firm the foam feels when you sit on it. A lower number feels softer and sinks more; a higher number feels supportive and springy. Density and firmness are independent, so a foam can be durable and still plush.

Matching Foam to Your Project

• Seat cushions: choose high-density foam with medium to firm support.
• Back cushions and pillows: softer foam adds comfort where less weight is applied.
• Benches and window seats: firm foam keeps edges crisp and level.
• Outdoor seating: look for open-cell foam designed to drain and dry quickly.

Compare the cushion foam options below to find the grade that fits your next project.