Best Sofa Bed Mattress: What Makes One Last and Feel Comfortable

When you buy a sofa bed mattress, a padded layer designed to serve as both a couch cushion and a sleeping surface. Also known as a daybed mattress, it needs to handle daily sitting, nightly folding, and years of weight without collapsing or losing shape. Most people assume any thick foam will do—but that’s where things go wrong. A best sofa bed mattress isn’t about thickness alone. It’s about how the layers work together: the support core, the comfort layer, and the cover that breathes but doesn’t stretch out.

A good one uses high-density foam or pocket springs inside, not just cheap polyurethane that turns to mush after six months. You’ll find the best ones have at least 4 inches of supportive foam, often with a quilted top that stays flat even after repeated use. The frame matters too—without a sturdy wooden or metal frame holding the mattress in place, even the best mattress will sag or slide. And don’t ignore the cover. It needs to be durable cotton or a blend that resists stains and doesn’t trap heat. If it feels like plastic, it’ll make your nights sweaty and your back sore.

People who use their sofa bed every night need more than a guest-room afterthought. They need something built for motion, pressure, and time. That’s why some models include zoned support, where the middle section is firmer to hold up hips and shoulders. Others use memory foam with cooling gel to stop that sticky, overheated feeling. And while you might think a 6-inch mattress is enough, anything under 5 inches usually bottoms out fast. Look for ones rated for daily use, not occasional guests.

What you’re looking for isn’t a fancy brand name—it’s transparency. Brands that tell you the foam density (aim for 1.8 lb/ft³ or higher), the spring count, and the fabric weave are the ones worth trusting. If they just say "premium comfort," walk away. The sofa bed frame, the metal or wooden structure that holds the mattress and allows it to fold. Also known as a conversion mechanism, it’s just as important as the mattress itself. A weak frame will twist, creak, or break long before the mattress wears out. And if the mattress doesn’t lie flat when opened, you’re sleeping on a hill, not a bed.

There’s no magic number for price, but if you’re spending less than £200 on a full-size sofa bed mattress, you’re probably paying for looks, not longevity. The best ones cost more upfront but save you from replacing it every two years. You’ll find real value in models that combine firm support, breathable fabric, and a design that folds smoothly without pinching the material. And yes—some of the top-rated ones come from brands you’ve never heard of, because they focus on function, not flashy ads.

What follows are real tests, user reviews, and expert breakdowns of what actually works. You’ll see which mattresses hold up after 100+ uses, which ones trap heat, and which ones feel like sleeping on a cloud without sinking into a hole. No fluff. No marketing hype. Just what you need to know before you buy your next sofa bed mattress.