Mattress Firmness Guide: Soft, Medium or Firm?

Firmness is the setting people most often get wrong. Here is how position, weight and preference should drive the choice.

Firmness describes how hard or soft a mattress feels when you lie on it. It is the setting people most often get wrong, because the label on the box is only part of the picture. Here is how to choose well.

The 1 to 10 firmness scale

Most brands rate firmness from 1 (very soft) to 10 (very firm). A 5 or 6 is generally called medium, and 7 to 8 is medium-firm to firm. The scale is not standardized between brands, so a "medium" from one maker can feel firmer or softer than another. Use it as a starting point and rely on how the bed feels to you.

Choose by sleeping position

Side sleepers

Side sleeping concentrates weight on the shoulders and hips. Many side sleepers prefer a soft to medium feel that lets those areas sink slightly so the spine stays in line.

Back sleepers

Back sleepers usually do well on medium to medium-firm surfaces that support the lower back without pushing against it.

Stomach sleepers

Stomach sleepers generally need a firmer surface so the hips do not sink below the shoulders and curve the lower back.

Combination sleepers

If you change positions through the night, a medium feel with some responsiveness is the usual compromise.

Body weight changes how a mattress feels

The same mattress feels softer to a heavier sleeper and firmer to a lighter one, because heavier people compress the comfort layers more. Heavier sleepers often prefer a firmer or thicker, denser build; lighter sleepers often prefer a softer feel to get the pressure relief the mattress was designed to deliver.

Couples with different preferences

When two people want different firmness, there are a few options. Pick a medium that works for both, choose a mattress with a responsive top layer, or consider a Split King, which uses two Twin XL mattresses so each side can have its own feel.

Preference beats rules

These are starting points, not rules. Plenty of side sleepers sleep well on firm mattresses and plenty of stomach sleepers love a plush top. If something does not feel right after several nights, the mattress is the wrong one for you, whatever the category.

How to test firmness

• Lie in your normal sleeping position for at least ten minutes, not one or two
• Check that your spine looks straight from the side, not sagging or bowed
• Put a hand under your lower back; a large gap suggests too firm, no gap suggests too soft
• Try your partner's position too, and roll over to test how easy it is to move
• Remember that new mattresses can feel a little firmer for the first few weeks

Testing at home

The best test is your own bedroom. That is why we deliver and set up first, and you pay only after you have inspected the mattress in your room.