Independent mattress research • Affiliate-supported • Disclosure

Latex Mattress Firmness & ILD

ILD can help describe foam resistance to compression, but it is not a universal comfort score.

The essential idea

ILD can help describe foam resistance to compression, but it is not a universal comfort score.

FactorWhat it means
ILDHigher values generally indicate firmer foam within a comparable test/material system.
ThicknessA thicker layer can behave differently from a thinner layer at the same nominal firmness.
Layer orderThe material closest to the sleeper strongly influences initial feel.
SleeperBody size and sleep position change how deeply the mattress is loaded.

How to use this when shopping

Treat material terminology as the beginning of the comparison, not the conclusion. Ask how the material is used in the complete mattress, how firmness is described, what support the bed requires and what happens if the feel is wrong.

For a real-world example of modular latex construction, see our Spindle Mattress review.