upholstery foam ild chart

An upholstery foam ILD chart is the quickest way to stop guessing about cushion comfort. ILD, short for indentation load deflection, measures how much force it takes to compress foam by a set amount. The higher the number, the firmer the foam feels when you sit, lean, or lie on it.

How to Read a Foam Firmness Chart

Most charts group foam into general firmness ranges. Exact numbers vary by manufacturer, so treat these as typical guidance rather than fixed rules:

• Soft (lower ILD): Seat backs, throw pillows, and toppers where you want plush give.
• Medium (mid-range ILD): Everyday sofa and dining chair seats that balance comfort and support.
• Firm (higher ILD): Window seats, benches, and outdoor cushions that need to hold their shape.

ILD vs. Density

ILD describes feel, while density relates to durability. A soft foam can still be high density and long lasting, so check both ratings before you buy.

Tips for Choosing

Consider who uses the seat, how often, and how thick the cushion will be. Thinner cushions usually need firmer foam to avoid bottoming out.

Ready to build cushions that feel just right? Browse the upholstery foam options below and compare firmness for your project.