Soft vs Medium vs Firm Mattress: Which Comfort Level Is Right for You?

Choosing between a soft, medium, or firm mattress is one of the most common decisions in mattress shopping — and one of the hardest, because none of the three is universally better than the others. The right firmness depends on how you sleep, your body weight, your personal comfort preference, and how the mattress is engineered to deliver that firmness. A "medium-firm" from one brand can feel very different from a "medium-firm" from another.

This guide compares the three firmness levels side by side, explains how sleeping position and body weight shift the calculus, breaks down the most common firmness myths, and shows how our Koala range covers medium-firm through firm across four different mattresses — including our flippable Core, which lets you try both medium-firm and firm within a single mattress. If you're deciding between comfort levels, this is where the practical comparison lives.

Soft, medium and firm mattresses each offer different comfort and support characteristics. Soft mattresses provide plush cushioning and pressure relief; medium mattresses balance comfort with support; firm mattresses offer a more supportive surface with less contouring. The best firmness depends on your sleeping position, body type, and comfort preference — not on any firmness level being universally better. Our Koala Core offers both medium-firm and firm via its flippable design; other Koala mattresses have their own comfort profiles.

Key takeaways

• Soft, medium and firm mattresses each suit different sleepers — no firmness is universally best

• Sleeping position, body weight, and personal preference all shift which firmness fits you

• The industry firmness scale runs 1-10 (1 = softest, 10 = firmest); most quality mattresses sit between 4 and 8

• Brand-to-brand firmness labels aren't standardised — "medium-firm" from one brand can feel different from another

• Our Koala Core is flippable (medium-firm on one side, firm on the other) — a low-risk way to try both firmness levels within a single mattress

What do soft, medium and firm actually mean?

The mattress industry uses a firmness scale from 1 to 10, where 1 is softest and 10 is firmest. Most quality mattresses sit between 4 and 8 — the extremes at each end are rare and often uncomfortable for most sleepers.

Standard firmness labels on the 1-10 scale:

• Soft — typically 3-4 out of 10; plush cushioning, deep contouring

• Medium-soft — around 4-5; noticeably softer than average

• Medium — around 5-6; balanced comfort and support

• Medium-firm — around 6-7; slightly firmer than balanced, common industry default

• Firm — around 7-8; supportive surface with less sink-in

• Extra-firm — 8-10; minimal contouring, very supportive (uncommon and often uncomfortable)

Perceived firmness varies by sleeper. The same mattress can feel medium to one person and firm to another based on body weight, sleeping position, and reference point (what mattress you're comparing it to). This is why firmness labels aren't a substitute for testing the mattress in-bed.

Why brand comparisons aren't reliable. A "medium-firm" foam mattress from one brand can feel very different from a "medium-firm" pocket spring mattress from another. Construction type, comfort layer thickness, and materials all shape how firmness feels — not just how it's labelled. Use firmness ratings as a rough guide, then confirm the fit through a proper sleep trial.

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Soft vs medium vs firm mattress: what's the difference?

The core comparison.

How to read this comparison:

• No firmness is objectively better than another — they suit different sleep styles, body types, and preferences

• Individual construction matters more than firmness label — a well-engineered firm mattress can outperform a poorly-engineered medium mattress, and vice versa

• Medium is the most common default because it suits the widest range of sleepers — but common doesn't mean best-for-you

• Feel-testing is essential — a proper sleep trial reveals what firmness labels can't

The rest of this guide walks through the factors that shift the "right" firmness for you — sleeping position, body weight, material, and preference.

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Which mattress firmness is best for your sleeping position?

Your sleeping position is one of the strongest predictors of which firmness fits you. Here are typical preferences.

Reader-focused framing: these are starting points, not rules. Individual comfort varies. A back sleeper who runs hot might prefer firmer because it allows better airflow. A side sleeper with a heavier build might prefer medium-firm because softer options compress too much under weight.

When multiple positions apply. If you change positions across the night — which most people do — think about which position you spend the most time in, or default to medium as a balanced starting point. Combination sleepers benefit from responsive constructions that reshape quickly under position changes.

Continue learning:

• Best Mattress for Side Sleepers

• Best Mattress for Combination Sleepers

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Does body weight affect mattress firmness?

Yes — significantly. Body weight affects perceived firmness because the mattress compresses more under heavier bodies and less under lighter bodies. The same mattress can feel firm to a lightweight sleeper and medium to a heavier sleeper.

Three body-weight profiles:

Lightweight sleepers (under 65kg).

Lighter sleepers often experience mattresses as firmer than their label suggests — because their body weight doesn't compress the comfort layers as deeply. A "medium-firm" mattress can feel firm-to-extra-firm to a lightweight sleeper. Lighter sleepers typically benefit from softer options (medium to medium-firm) that allow the comfort layers to activate under lower body weight.

Average-weight sleepers (65-90kg).

Sleepers in this range have the most flexibility. Most firmness options work reasonably well. Choose based on sleeping position and personal preference rather than defaulting to a specific firmness. This is the range where medium-firm — the industry default — typically works well.

Heavier sleepers (90kg+).

Heavier sleepers often experience mattresses as softer than their label suggests — because their body weight compresses the comfort layers more deeply. A "medium" mattress can feel medium-soft. Heavier sleepers typically benefit from firmer options (medium-firm to firm) that provide adequate support without excessive sinking.

Couples with different body weights should test the mattress together across a proper trial. Firmness that suits one partner may feel wrong to the other. Flippable mattresses (like our Core) can help by giving partners different firmness options within the same mattress.

Continue learning: Best Mattress for Lightweight Sleepers.

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Does mattress material affect firmness?

Yes — how firmness is engineered varies by construction type.

All-foam mattresses (like our Kloudcell® range).

Firmness is delivered through foam density and layer engineering. Kloudcell® mattresses feel consistent across the mattress surface — the same firmness across the whole bed. All-foam construction typically delivers stronger motion isolation than spring alternatives at the same firmness level.

Pocket spring mattresses.

Firmness is delivered through spring gauge and pocket construction. Pocket springs can be zoned — different firmness across different areas of the mattress. Pocket spring mattresses tend to feel more "on top" and less "sink-in" than foam at the same firmness rating.

Latex mattresses.

Firmness varies by natural vs synthetic composition and by Dunlop vs Talalay processing. Dunlop latex tends to feel firmer; Talalay latex tends to feel softer. Latex typically feels responsive with slight bounce compared with memory foam or Kloudcell®.

Hybrid mattresses.

Firmness is delivered through the combination of spring core and foam comfort layers. Hybrid firmness varies significantly by construction — a hybrid with a thick foam comfort layer feels softer than a hybrid with a thin comfort layer, even at the same rated firmness.

Key point: firmness is influenced by both material and construction integration. A "medium-firm" foam mattress feels different from a "medium-firm" pocket spring mattress, even at the same firmness rating. When comparing across constructions, test in-person rather than trusting the label.

Continue learning:

• Mattress Layers Explained

• What Is a Pocket Spring Mattress?

• What Is a Latex Mattress?

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How Koala helps you find the right mattress firmness

Our range covers medium-firm through firm, with each mattress designed for a specific comfort profile. If you're unsure which firmness suits you, we've built the range to give you meaningful options — including a flippable mattress that lets you try two firmness levels within a single purchase.

Important clarifications about our range's firmness options:

Only the Koala Core is flippable. Our Plus, Luxe, and SE are not flippable and don't have adjustable firmness — each is designed with a specific comfort profile. The Core is the mattress in our range that lets you try both medium-firm and firm within a single purchase.

7 multi-layered support zones apply only to the Koala Luxe (per Luxe product page). Our Core, Plus, and SE mattresses don't feature zoning.

Our range doesn't include a traditionally plush "soft" mattress. If you're specifically seeking a plush-soft feel, see Best Soft Mattress Australia for context on soft mattress options in Australia. Our range starts at medium-firm — a deliberate design choice, because medium-firm suits the widest range of sleepers and delivers the balance between comfort and support most sleepers benefit from.

Kloudcell® is proprietary open-cell foam — not memory foam, not latex, not hybrid. It's a separate material category with responsive contouring, airflow, and motion absorption engineered into it.

What every mattress in our range delivers:

• CertiPUR-US® certified Kloudcell® open-cell foam

• 120-night trial

• 10-year mattress warranty

• Australian design + our Sydney showroom for in-person testing

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Common mattress firmness myths

Firmness is one of the most myth-heavy topics in mattress shopping. Here are the ones worth clearing up.

The underlying reality: firmness marketing sells simplicity — "firm = supportive = better for backs" — but the actual relationship between firmness, support, and sleep quality is more nuanced. Trust construction quality and in-bed testing over marketing shorthand.

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How to choose the right mattress firmness

Six factors to weigh when deciding between soft, medium, and firm.

1. Sleeping position.

Side sleepers lean soft-to-medium; back sleepers lean medium-to-firm; stomach sleepers lean firm; combination sleepers lean medium. Consider which position you spend the most time in.

2. Body weight.

Lighter bodies often prefer softer options because firm mattresses feel firmer than their label suggests. Heavier bodies often prefer firmer options because softer mattresses compress too deeply. Average-weight sleepers have more flexibility.

3. Comfort preference.

Do you like sinking into the mattress ("hug" feel) or resting on top of it ("float" feel)? Preference matters even when position and weight suggest otherwise. Some side sleepers prefer firmer mattresses because they dislike the "sinking" sensation; some back sleepers prefer softer because they like contouring.

4. Mattress construction.

Foam, pocket spring, latex, and hybrid all deliver firmness differently. A "medium-firm" foam mattress feels different from a "medium-firm" pocket spring. Consider construction type alongside firmness rating.

5. Partner preferences.

If sharing a bed, factor in both sleepers. Firmness that suits one partner may feel wrong to the other. Flippable mattresses (like our Core) can accommodate partner disagreement within a single purchase. Alternatively, split-firmness mattresses from some brands offer different firmness on each side.

6. Trial period.

The only reliable way to test firmness is at home over multiple weeks. Marketing claims and showroom testing don't reveal how a mattress will feel after 30 nights of your actual sleep. Our 120-night trial gives you time to be sure.

Editorial framing: the "right" firmness isn't a formula — it's a fit. Use these factors as guidance, not as rules. If you're stuck between two firmness levels, start with the flippable Core, or lean toward medium-firm as the widest-suiting default.

Choosing between soft, medium, and firm comes down to fit — not to any firmness being objectively better than another. Sleeping position, body weight, and personal preference all shape what works. If you're stuck between two options, try the firmness that most closely matches your position and weight profile, then confirm through a proper sleep trial. And if you're genuinely unsure between medium-firm and firm, a flippable mattress is a low-risk way to test both within a single purchase — the right firmness will make itself clear across a few weeks of actual sleep.

Not sure which firmness is right for you?

If you're deciding between comfort levels, our Koala range gives you meaningful options — including the flippable Koala Core (Koala Mattress), where medium-firm sits on one side and firm on the other. Try both, settle on the one that suits you, and let the 120-night trial confirm the fit. If premium comfort or cooling matters more than firmness flexibility, our Luxe and Plus offer their own comfort profiles engineered for different sleep priorities. Every mattress in our range comes with a 120-night trial and a 10-year warranty.

Shop Koala Mattresses →

Still comparing mattress comfort? Read our guides on Best Soft Mattress Australia, Mattress Layers Explained, and How to Choose a Mattress to better understand how firmness, construction, and comfort work together.

To compare in person, visit our Moore Park Showroom in Sydney.