How to choose the right mattress: types, firmness and sizes

Reviewed by the Beliani Content Team · Updated September 2026

A mattress only earns its price if its type, firmness and size genuinely match how you sleep, your body weight and the bed frame underneath it. Getting these three decisions right affects comfort for years, since a mismatched mattress is expensive and inconvenient to replace early.

Three things to get right

Every good mattress choice comes down to the same three decisions, in this order.

Which mattress type is best?

Every mattress type trades off support, temperature, motion isolation and price differently. Here's how the main constructions compare.

Memory foam vs classic foam: what's the difference?

Both are foam mattresses and both offer customised, contouring support, but they don't behave the same way. Memory foam conforms more closely to the body, giving stronger cushioning and motion isolation, which suits couples and anyone wanting a highly personalised feel. Classic foam is more resilient and breathable, with a bouncier response and a generally lower price, at the cost of some of that close contouring.

Memory foam vs latex: which contours better?

Memory foam contours most closely to the body and is the strongest choice for isolating a partner's movement, but it retains more heat unless gel-infused. Latex is more responsive, sleeps cooler and is naturally resistant to dust mites, which suits hot sleepers or anyone wanting a more natural material, even though it doesn't sink in quite as deeply.

What mattress firmness is best for your sleeping position?

Firmness needs change with how you sleep. Here's what each position needs from a mattress.

Beyond firmness, each position has its own priority: side sleepers need the mattress to contour closely at the shoulders and hips, back sleepers need minimal sinkage to keep the back in a more even, level position, and stomach sleepers need enough lift to stop the hips dropping and the lower back arching.

Mattress firmness and body weight

Body weight has the clearest effect on which firmness will actually support you, on top of sleeping position. Heavier bodies sink further into any given foam or spring, so they generally need a firmer surface to get the same support a lighter person feels on medium. As a rough guide: under 60kg tends to suit soft to medium, most sleepers up to around 110kg do well on medium, and anyone heavier, or any dedicated stomach sleeper, is usually better on firm.

Still unsure? A double-sided mattress with two firmness levels, one on each side, lets you flip and compare rather than committing to one feel.

What are the standard mattress sizes?

Match the mattress size to your bed frame and room before firmness or type — the wrong dimensions rule out every other choice.

What is a 7-zone mattress?

A 7-zone mattress divides the sleeping surface into seven areas, each with different firmness, so the head, shoulders, lumbar region, hips and legs each get support suited to that area instead of one uniform feel across the whole bed.

• Targeted firmness at the lower back, neck and shoulders spreads weight more evenly across the body.
• Weight is distributed away from the hips and shoulders for a more even feel across the mattress.
• Support sits where it's needed most, keeping the body in a more even, level position.
• Zoning reduces disturbance from a partner's movement through the night.
• Even weight distribution means less need to shift position during the night.
• The layout suits back, side and stomach sleepers without needing a fully custom build.

Mattress lifespan and maintenance

Most mattresses last 7 to 10 years with proper care. Foam and latex sit at the longer end of that range; entry-level spring mattresses often need replacing closer to 6 - 8 years under daily use. Two features worth checking before you buy: handles, which make flipping or rotating easier, and a removable, OEKO-TEX certified cover, which simplifies cleaning.

• Rotate the mattress every 3 to 6 months to wear it evenly and prevent sagging.
• Use a mattress protector to guard against spills, stains and dust mites.
• Vacuum periodically to clear dust, and air it out with open windows when you can.
• Avoid standing or jumping on it, which can damage springs or foam layers permanently.
• Flip a double-sided mattress occasionally for even wear across both sides.

Shop now: mattresses

Accessories that extend a mattress's comfort

Not ready to replace the mattress but want it to feel different tonight? A topper or protector changes the feel and adds protection without a full replacement, and pairing it with the right duvet rounds out the setup.

Shop now: toppers and protectors and duvets and comforters

What to check before buying

Before you commit, run through these checks in order.

• Firmness suited to your main sleeping position and body weight, not just personal preference
• Mattress width and length match your bed frame exactly, with no overhang or gap
• Enough clearance in the room to make the bed and walk around it once the size is chosen
• A removable, OEKO-TEX certified cover if you want easier cleaning
• Handles on the sides for rotating a heavier mattress every few months
• A trial period and warranty length that gives you time to adjust before committing long-term

Frequently asked questions