Guide
Best foam for seat cushions
On this page (8)
The best foam for a seat cushion you use every day is a supportive polyurethane foam with a polymer density of at least 1.8 lb/ft³ (29 kg/m³) and a support factor of 2.0 or above. The Polyurethane Foam Association (PFA) reports that foams at or above that density perform better in seating, and that foams with that support factor suit load-bearing uses such as furniture seat cushions.
Foamera makes made-to-measure foam cushions and sells them online through TURKEX LLC. On Foamera product pages you choose the fill, and High Density Foam is the choice the product page describes for daily use.
What should I look for in seat cushion foam?
| Property | What it tells you | What to look for in a seat |
|---|---|---|
| Polymer density | Durability and support | 1.8 lb/ft³ (29 kg/m³) or higher |
| Support factor (65% IFD ÷ 25% IFD) | How well the foam supports weight without bottoming out | 2.0 or above |
| Firmness (25% IFD) | How the surface feels | Your preference; firmness is independent of density |
| Compression set | Height lost with use | Lower is better; it decreases as density goes up |
Is firmer foam better for a seat cushion?
Not necessarily: firmness describes the surface feel, while support comes from the support factor and density. PFA notes that a foam with a low 25% IFD and a high support factor can feel soft on the surface without bottoming out.
What does bottoming out mean?
Bottoming out is a lack of support under full weight, when the cushion compresses down to the furniture base. PFA notes that seating foams with low support factors are more likely to bottom out.
Is memory foam good for a seat cushion?
Memory foam recovers slowly and conforms to the body, and PFA notes that it may bottom out if its firmness is very low and its density or thickness is not enough. Memory foam is not a fill choice on Foamera product pages; see HD foam vs memory foam.
Can I make a firm seat feel softer?
Yes. PFA notes that foam seat cushions are frequently wrapped with polyester or cotton batting to make the surface softer. On Foamera product pages you can add a Fiber Wrap, described there as a layer of soft polyester fiber wrapped around the foam core.
How thick should a seat cushion be?
Thickness depends on the seat and how you use it; the cushion thickness guide covers thickness by use.
How do I order seat foam cut to size?
Custom sizes, foam and fabric are chosen on each product page, and sizes can be entered in inches or centimetres. Measure first with the measuring guide, then start with chair cushions, the square seat cushions, the bench cushions or the window seat and nook cushions.
Which guide should I read next?
- Foam density guide
- Best foam for couch cushions
- HD foam vs memory foam
- What foam and fill Foamera uses
Sources
- Polyurethane Foam Association, Foam Performance, Glossary and Furniture Case Study. Accessed 26 September 2026.
- Polyurethane Foam Association, IN•TOUCH Vol. 1 No. 2, The Importance of Density (revised 2016). Accessed 26 September 2026.
- Polyurethane Foam Association, IN•TOUCH Vol. 11 No. 1, Viscoelastic (Memory) Foam (revised 2016). Accessed 26 September 2026.
- Fill choices and extras: Foamera product pages.