How to Read a Mattress Construction Spec Sheet
Learn which mattress specifications matter, which are marketing, and how to read foam density, IFD, coil gauge, zoning and layer thickness.
A useful mattress specification sheet should tell you what each layer is, how thick it is, and which measurable property supports the brand’s claim. Most do not. This guide shows how to separate disclosed construction from marketing—and how to leave an unknown blank instead of guessing.
| Specification | What it tells you | What it does not tell you |
|---|---|---|
| Thickness | How much vertical space a layer occupies | Quality or firmness |
| Foam density | Mass per cubic foot; a durability clue | Firmness |
| IFD / ILD | Force needed to compress a foam sample | Whole-mattress feel |
| Coil gauge | Wire thickness; lower number means thicker wire | Quality without coil design and placement |
Start with the layer stack
Read from the cover down. Record the quilt package, each comfort and transition layer, the support core, and the base foam. Add the published thicknesses. If they do not roughly match the advertised mattress height, the sheet is incomplete; covers, fire barriers and rounding can explain a small difference, not several missing inches.
Separate material identity from performance
“Premium foam” is not a specification. Useful foam fields are material family, thickness, density and IFD or ILD. Useful coil fields are type, height, wire gauge, zoning and edge design. A trade name can identify a formulation, but it cannot substitute for those fields.
Read provenance beside the number
A manufacturer-published figure and a Yawnder measurement are different evidence. Our review construction tables label brand-published specifications and keep them separate from our instrument readings. If two credible sources disagree, we preserve the disagreement rather than average it.
Use the specification in context
A 3.5 lb memory-foam layer can be a reasonable comfort material; 3.5 lb conventional polyfoam means something different. A 14.5-gauge coil can contour well in the center while a lower-gauge perimeter reinforces the edge. Layer role, thickness and placement matter as much as the isolated number.
Related construction guides
For short definitions, use the Yawnder sleep glossary. For measured performance, see how we test and score mattresses.
Frequently asked questions
What is the most important mattress specification?
There is no single winner. For foam, start with material, thickness and density. For springs, start with coil type, gauge and zoning. Then compare those facts with measured performance.
Why do brands omit density or gauge?
Some treat formulations as proprietary; others publish simplified marketing pages. An omitted value is unknown, not automatically bad—and it should never be invented.
Should layer thicknesses equal mattress height?
They should be close. Quilting, covers, fire barriers and rounding can add height, but a large unexplained gap deserves a question.
Where can I compare real examples?
Open a Helix review with Yawnder’s “What’s inside” table, then use this center to decode each field.