Mattress Firmness Calculator: What Firmness Do I Need?

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Mattress Firmness Calculator

What firmness do you need? Answer five questions about how you sleep, and get a firmness range on a 1–10 scale, the reasons behind it, and the mattresses we review that fall inside it.

The Calculator

What Firmness Do I Need?

1. How do you usually sleep?

2. What do you weigh?

3. Do you have lower back pain?

4. Which feel do you prefer?

5. Do you share the bed?

Please answer all five questions.

The Scale

Mattress Firmness Scale, Explained

Brands rate firmness from 1 (softest) to 10 (firmest), but there is no shared standard, so one brand’s 7 can feel like another’s 6. We use the figure on each of our own reviews.

RatingNameHow it feelsUsually suits
1–4SoftYou sink well in; the mattress wraps around youLighter side sleepers
5–6MediumClear give at the shoulder and hip, still supportiveMost side sleepers
6.5–7.5Medium-firmSome give on top, firm underneathBack sleepers, combination sleepers, back pain
8–8.5FirmLittle sink; you lie on the surfaceStomach sleepers, heavier bodies
9–10Extra firmAlmost no giveHeavier stomach and back sleepers who want maximum push-back
The Chart

Mattress Firmness Chart by Position and Weight

The calculator starts from this chart and then adjusts for back pain and the feel you prefer.

PositionUnder 60 kg60–100 kg100–130 kgOver 130 kg
Side5–65.5–6.56–76.5–7.5
Back6–76.5–7.57–87.5–8.5
Stomach6.5–7.57–87.5–8.58–9
Combination5.5–6.56–76.5–7.57–8

A starting point, not a rule. Side sleepers need give at the shoulder and hip; back and stomach sleepers need the hips held level; heavier bodies sink further into any mattress, so they need a firmer one to feel the same.

FAQ

Mattress Firmness Questions

What firmness is best for back pain?
Medium-firm, around 6.5 to 7.5 out of 10, for most people. In a randomised trial of 313 adults with chronic lower back pain (Kovacs and colleagues, The Lancet, 2003), those on medium-firm mattresses reported less pain and disability than those on firm ones, and a 2015 systematic review (Radwan and colleagues, Sleep Health) found medium-firm designs best for comfort, sleep quality and spinal alignment. Our back pain guide ranks the options.
What firmness do side sleepers need?
Usually medium, about 5.5 to 6.5. The shoulder and hip need to sink in far enough to keep the spine straight; too firm and the shoulder takes the pressure. See our side sleepers guide.
Should heavier people buy a firmer mattress?
Generally a little firmer, and more importantly one with strong support and edges. A heavier body sinks further into any mattress, so a medium can feel soft. Our guide for heavier sleepers covers the mattresses built for it.
Is one brand’s 7/10 the same as another’s?
No. There is no industry standard for the scale, so treat brand numbers as a guide. The calculator uses the figure or wording on our own review of each mattress, and for three mattresses where no number is given it uses the description instead.
What if my partner and I want different firmness?
Look at mattresses you can adjust. Sleeping Duck lets each side of the bed have its own firmness; Ecosa and OneBed let you rearrange layers to change the whole mattress; Koala flips between two firmness levels. Our couples guide goes through the options.
What firmness is right for children and babies?
For babies, safe sleeping guidance from Red Nose Australia is a firm, flat, well-fitting mattress, with nothing soft on top. Older children generally do well on a supportive medium-firm mattress; they are light, so most feel softer to them than to an adult.

Continue your research

→ Take the Mattress Quiz → Sleep Calculator: What Time Should I Go to Bed? → Best Mattress for Back Pain Australia → Best Mattress for Side Sleepers Australia → Best Firm Mattress Australia

General guidance only. Firmness figures come from our own reviews; brands rate firmness differently, and how a mattress feels also depends on your body and your bed base. If back pain is severe, getting worse or comes with other symptoms, see your GP or a physiotherapist. We do not physically test mattresses: our scores come from owner reviews, independent awards, published specifications and warranty terms.

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