Firmness
Mattress Firmness Guide
Firmness scales are useful within a brand, but they are not standardized across the mattress industry.
Use your current mattress as a reference
Ask whether you want more surface cushioning, more resistance to sinking, or roughly the same feel. That is more useful than chasing a supposedly universal number.
Separate firmness from support
A mattress can feel soft at the surface while still using a strong support core. Firmness is perceived feel; support is how the full construction manages load.
See a real three-model example in our Aviya firmness guide.