Mattress Firmness Levels Explained

Buying a new mattress should be exciting. It’s basically the start of a long term relationship. But walk into any showroom and suddenly you’re hit with terms like soft, medium, firm, medium-firm, extra-firm-but-not-too-firm… and you start wondering if you need a degree in mattressology just to sleep well.

Don’t panic. Let’s break it down into plain English (with no sleep science snobbery).

🛏️ What “Firmness” Actually Means

Firmness is simply how a mattress feels when you lie on it. Soft and luxurious, balanced and bouncy, or solid and supportive.

👉 Important: Firmness isn’t the same as support.

Support = how well the mattress keeps your spine aligned.

Firmness = how squishy or sturdy it feels on the surface.

So yes, a soft mattress can still be supportive, and a firm one can be a bad match if it doesn’t suit your body.

💤 Who Should Choose What?

Here’s where things get interesting. The right firmness isn’t about what sounds comfiest... it’s about your sleeping position, body type, and personal preference.

🌙 Soft

Feels like: Sinking into a fluffy hotel bed.
Best for:

• Side sleepers who need cushioning for shoulders and hips.
• Lighter people (under ~10 stone/65kg) who don’t sink much.
• Anyone who likes the “hugged” feeling.

⚠️ Watch out: Too soft, and your back may dip out of alignment.

☁️ Medium

Feels like: Balanced, soft enough to feel cosy, firm enough to feel supported.
Best for:

• Combo sleepers (you switch between back, side, and stomach).
• Couples with different preferences (the compromise option).
• People who just want something that “works” without overthinking.

This is the most popular choice — because it suits the widest range of sleepers. 

🪵 Firm 

Feels like: Sleeping “on” the mattress, not “in” it.
Best for:

• Back or stomach sleepers who need strong spinal alignment.
• Heavier people (over ~15 stone/95kg) who need more pushback.
• Anyone who hates that sinking feeling.

⚠️ Watch out: Too firm can feel unforgiving and cause pressure points.

🤔 Medium-Firm: The Crowd Favourite

If you’ve ever noticed that every other mattress review says “medium firm”, you’re not imagining things. That’s because it tends to tick the most boxes:

• Enough softness for comfort.
• Enough firmness for support.
• Suits most body types and sleep positions.

Think of it as the “denim jeans” of mattresses: works for pretty much everyone, but maybe not your perfect fit.

🕵️ How to Pick YOUR Firmness

Here’s a quick checklist:

• • Side sleeper? → Soft to medium.
  • Back sleeper? → Medium to firm.
  • Stomach sleeper? → Firm (to keep your hips from sinking).
  • Lightweight? → Softer feels comfier.
  • Heavier? → Firmer keeps you supported.
  • Sharing a bed? → Medium firm (so everyone's happy).

And if you’re still unsure? Try before you buy, or choose a mattress with a home trial period. Your body will tell you within a week if it’s happy.

✅ Final Word

Choosing mattress firmness doesn’t have to be complicated. Think about how you sleep, your body type, and how you like your bed to “feel.” The good news? There’s no wrong answer... just the one that gives you the best night’s sleep.