Mattress firmness guide
Firmness decides more about how a mattress feels than foam type, thickness or price. It is also the thing brands describe least consistently — one company's "medium" is another's "firm". This mattress firmness guide explains the scale, then shows how to choose using the two things that matter most: your body weight and how you sleep.
The firmness scale, explained
Most brands use a rough 1–10 scale, where 1 is extremely soft and 10 is extremely firm. Nobody regulates it, so treat numbers as a comparison within one brand rather than a universal measure.
| Scale | Label | How it feels |
|---|---|---|
| 1–2 | Very soft | You sink deeply; rare in practice |
| 3–4 | Soft | Plush, noticeable sink, strong contouring |
| 5 | Medium | Balanced — some give, some push-back |
| 6–7 | Medium-firm to firm | Supportive, you rest more on top |
| 8–10 | Extra-firm | Very little give; close to a hard surface |
Firmness by sleeping position
Side sleepers: soft to medium (roughly 3–5)
Your shoulder and hip are the widest points of your body. They need to sink in so your spine stays straight. Too firm and you get shoulder pain and numb arms. More in best mattress for side sleepers.
Back sleepers: medium to medium-firm (roughly 5–7)
The lower back needs to be supported without the hips sinking. Medium-firm is the usual sweet spot, and it is widely recommended for people with back pain.
Stomach sleepers: medium-firm to firm (roughly 6–8)
On a soft surface the hips drop and the lower back over-arches. Firmer keeps you flat.
Combination sleepers: medium (roughly 5–6)
If you change position through the night, a medium surface is the best compromise. Very soft memory foam can make turning over harder work.
Firmness by body weight
Weight changes how firm a mattress feels. The same mattress feels firmer to a light person and softer to a heavy one, because a heavier body compresses the foam further.
- Lighter sleepers — go a step softer than the position guide suggests. You may not weigh enough to press into a firm surface, so it feels hard.
- Average weight — follow the position guide as it is.
- Heavier sleepers — go a step firmer, and pay attention to the core. Dense HR foam holds its support under more weight for longer. A soft mattress may let the hips sink too far.
Signs your mattress is the wrong firmness
- Too soft: lower-back ache in the morning that eases as you move; feeling like you are climbing out of a hollow; hips lower than shoulders when you lie on your back.
- Too firm: shoulder or hip soreness; arms going numb when on your side; tossing and turning to find a comfortable spot; a gap you can slide a hand into under your lower back.
Couples with different needs
If one of you needs soft and the other firm, a medium mattress is a compromise that may suit neither perfectly. Options include a reversible mattress with a different firmness on each face, or a topper on one side. Our best mattress for couples guide covers this.
How our mattresses map to the scale
- Memory Luxe — soft, 3/10. Lighter side sleepers and joint pressure relief. Not for stomach sleepers.
- SensiCore — medium, 5/10. Side and combination sleepers, most couples.
- Orthopaedic Pro — medium-firm, 6/10. Back sleepers and lower-back discomfort.
- Spine Shield — extra-firm, 8/10. Heavier back or stomach sleepers who want it very firm. Unforgiving for side sleepers.
- Dual Comfort Pro — reversible: soft (3/10) on one face, firm (7/10) on the other. Useful if you're unsure, or your needs may change.
If a mattress turns out slightly firmer than you'd like, a thin soft topper is a reasonable fix; if it is far too firm or too soft, eligible items can be returned within 7 days. For the full buying process, read how to choose a mattress.
Frequently asked questions
Medium to medium-firm suits the widest range of sleepers. Adjust softer if you sleep on your side or are lighter, and firmer if you sleep on your stomach or are heavier.
Not always. Medium-firm is widely recommended for back pain. Extra-firm mattresses can leave the lower back unsupported and create pressure at the shoulders and hips.
Most foam softens slightly in the first few weeks, then settles. A good HR foam core keeps its support far longer than low-density foam.
A topper can make a mattress feel softer or slightly firmer on the surface. It cannot fix a sagging mattress or add real support to a worn-out core.