Mattress Firmness Guide

For us, firmness refers to how the comfort layer feels when you lie down. A thicker comfort layer or softer materials create more cushioning, while a thinner comfort layer or firmer materials create a more solid surface feel.

There is no single mattress firmness that is best for everyone. Research suggests that mattress firmness should be considered alongside factors such as sleeping position and body build. Our guide therefore starts with sleeping position, then uses BMI and age to refine the recommendation. 

Sleeping Position

Different sleeping positions place different amounts of pressure on different parts of the body, which can influence the amount of cushioning and firmness needed for comfortable support.

Side Sleepers

Side sleeping places more pressure on the shoulders and hips. A softer, thicker comfort layer provides better contouring and helps relieve pressure.

If the Mattress Is Too Firm or Too Soft
Too Firm · Higher Concern More pressure can build around the shoulders and hips, causing discomfort.
Too Soft · Moderate Concern Too much hip sinking may affect spinal alignment.
Recommended Firmness
Soft
Med. Soft
Medium
Med. Firm
Firm
Best match for most sleepers in this group
Also suitable depending on BMI or age
Side sleeper sample

Back Sleepers

Back sleeping distributes body weight more evenly. A balanced comfort layer supports the lower back while providing comfortable contouring.

If the Mattress Is Too Firm or Too Soft
Too Firm · Moderate Concern Too little contouring can leave insufficient support around the lower back.
Too Soft · Higher Concern Too much hip sinking can affect the natural alignment of the lower spine.
Recommended Firmness
Soft
Med. Soft
Medium
Med. Firm
Firm
Best match for most sleepers in this group
Also suitable depending on BMI or age
Back sleeper sample

Stomach Sleepers

A firmer comfort layer can help prevent the midsection from sinking too deeply, which may otherwise increase the arch in the lower back.

If the Mattress Is Too Firm or Too Soft
Too Firm · Lower Concern Too little cushioning may cause slight chest and stomach discomfort.
Too Soft · Higher Concern The midsection may sink too deeply, increasing the arch in the lower back.
Recommended Firmness
Soft
Med. Soft
Medium
Med. Firm
Firm
Best match for most sleepers in this group
Also suitable depending on BMI or age
Stomach sleeper sample

Combination Sleepers

Combination sleepers change positions throughout the night. A balanced comfort layer provides contouring without excessive sinking.

If the Mattress Is Too Firm or Too Soft
Too Firm · Moderate Concern May feel uncomfortable around the shoulders and hips when side sleeping.
Too Soft · Moderate Concern Too much sinking may affect spinal alignment based on sleeping position.
Recommended Firmness
Soft
Med. Soft
Medium
Med. Firm
Firm
Best match for most sleepers in this group
Also suitable depending on BMI or age
Combination sleeper sample

Body Mass Index

Body build and BMI can influence how your body interacts with different mattress firmness levels. Use your BMI as a secondary factor to adjust the best-match firmness for your sleeping position.

Lower BMI (<18)

People with a lower BMI generally exert less overall load on the mattress and may not sink as deeply into the comfort layers.

Recommended Adjustment

Starting from the best-match firmness for your sleeping position, consider going slightly softer for better contouring and pressure relief.

Light build BMI

Moderate BMI (18 - 28)

For sleepers within this range, start with the best-match firmness for your sleeping position. Normally, no adjustment is required.

Recommended Adjustment

No adjustment is required. Go for the best-match firmness based on your sleeping position and this should suit most people within this BMI range.

Average build BMI

Higher BMI (>28)

Greater body mass can result in deeper compression of a mattress's comfort layers, making firmness and support increasingly important.

Recommended Adjustment

Starting from the best-match firmness for your sleeping position, consider going slightly firmer for better stability and less sinking.

Heavier build BMI

Age

Age can affect how much cushioning and pressure relief feels comfortable. Use it to slightly adjust your firmness choice from the best match based on your sleeping position.

Kids

Children are still growing, so a supportive and stable sleep surface is important. Avoid a mattress that allows excessive sinking, while keeping the surface comfortable for their sleeping position.

Recommended Adjustment

Starting from the best-match firmness for their sleeping position, consider going slightly firmer to provide a more stable surface.

Kid on snow mattress

Adults

Most adults can use the best-match firmness for their sleeping position, with BMI providing a more meaningful adjustment where needed.

Recommended Adjustment

No adjustment is required. Go for the best-match firmness based on your sleeping position, then adjust according to BMI if needed.

Adult on snow mattress

Seniors

Comfort and ease of movement can become more important with age. A mattress should provide enough cushioning for pressure relief while remaining stable enough to make changing positions and getting in and out of bed comfortable.

Recommended Adjustment

Start with the best-match firmness for your sleeping position. If easier movement and a more stable surface are priorities, consider a slightly firmer option.

Senior on snow mattress

Firmness Recommendation

Enter your sleeping position, BMI and age below. We'll combine these factors to recommend the mattress firmness that best suits your needs.

Tell Us About Your Sleep Profile

Select the options that best describe you

1. Age

Select One

2. BMI

Select One

3. Sleeping Position

Select One

Your Personalized Recommendation

Complete your sleep profile to see:

✓

Your recommended mattress firmness

Looking to Buy a Mattress?

Explore our mattress collection if you are ready, or view our mattress buying guide to learn about the other factors to consider.

Mattress Collection Mattress Buying Guide

References

  1. Mattress Selection in the Management of Low Back Pain and Sleep Quality: A Systematic Review — Review of research on mattress ergonomics, firmness, body characteristics, age, sleeping position and sleep outcomes.
  2. Sleep Foundation — Mattress Firmness: Finding the Best Firmness for You — Guidance on mattress firmness in relation to sleeping position, pressure relief and body weight.
  3. Surface Electromyographic Responses During Rest on Mattresses with Different Firmness Levels in Adults with Normal BMI — Study examining mattress firmness, pressure distribution and anthropometric characteristics including BMI.
  4. Effect of Firmness of Mattress on Chronic Non-Specific Low-Back Pain: Randomised, Double-Blind, Controlled, Multicentre Trial — Randomised controlled trial comparing medium-firm and firm mattresses in adults with chronic non-specific low-back pain.