A practical reference
Use the same model, size, units and source date for every comparison. A missing specification is an open question, not a zero or a reason to invent a score.
Mass per unit volume, commonly lb/ft³ or kg/m³. Density and firmness are separate properties: a dense foam can still feel soft.
Ask the seller: Which layer and foam type does the number describe? Record the unit. Compare like materials and keep density separate from the mattress's firmness rating.
Indentation load or force deflection describes the force needed to compress a foam sample under specified test conditions. It is not the same as a retailer's 1–10 firmness scale.
Ask the seller: Ask for the test method, compression percentage, sample thickness and material. Without matching conditions, two numbers may not be comparable.
Gauge describes wire thickness; a lower gauge number means thicker wire. Count describes the number of coils, which can change with mattress size and include different coil layers.
Ask the seller: Record the mattress size, which coil layer is counted and any zoned gauges. Do not turn either number alone into a comfort or lifespan ranking.
Total mattress height does not tell you how much comfort material sits above the support core.
Ask the seller: Request a layer-by-layer breakdown with material and thickness. Note whether the quoted height includes the cover or quilting. Keep undisclosed layers marked as unknown.
A mattress recommendation, a bed frame's capacity and an adjustable base's load rating describe different things.
Ask the seller: Check each exact model's instructions. Ask whether a figure is per sleeper or total, and whether mattress and bedding weight count toward it. Never infer capacity from mattress weight or height.
Technical references checked September 12, 2026: PFA foam performance, PFA terminology and Saatva coil terminology. The manufacturer reference explains construction; it is not an independent product comparison.
Write “Not disclosed” and save the product page or support response with its date. Ask for the exact variant, rather than accepting a specification from another model in the same range. Keep seller statements separate from measurements you made yourself.
For example, “12-inch hybrid” leaves the comfort-layer thickness, foam density and coil specification unanswered. The next useful step is requesting that breakdown, rather than assigning the mattress a quality score.
Include the resource URL, exact model or row, what changed and a manufacturer source if available. This opens your email app; nothing is submitted automatically.
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