Everything You Need to Know About
Choosing the Perfect Mattress

Buying a mattress is one of the most important purchases you'll make — and yet most people spend less time choosing one than they do picking a sofa. A good mattress can transform your sleep, reduce back pain, and genuinely improve your daily energy levels. A poor one can do the opposite for years.

This guide cuts through the noise. Whether you're shopping for a double mattress, a small double for a compact room, or trying to decode the difference between memory foam and pocket springs, you'll find clear, honest answers below — plus our free Mattress Finder Tool to match you with the right choice in minutes.

What Size is a Double Mattress?

One of the most common questions we receive is: "What are the dimensions of a double bed mattress?" The answer varies slightly by country, which causes no end of confusion when shopping online. Here is a definitive breakdown.

All Standard Mattress Sizes Explained

Understanding all the sizes helps you plan properly — particularly if you're measuring your bedroom, buying a new bed frame, or ordering a mattress topper for a double.

Memory Foam vs Spring Mattress — Which is Better?

This is the great mattress debate, and the honest answer is: it depends on you. Both types have real strengths. The best choice comes down to how you sleep, your body type, and your priorities.

Memory Foam Mattresses

Memory foam was originally developed by NASA and is made from viscoelastic material that contours precisely to the shape of your body. It responds to heat and pressure, creating a "sinking in" sensation that many sleepers find deeply comfortable.

Spring (Pocket Sprung) Mattresses

Pocket spring mattresses contain individually wrapped coil springs. Each spring moves independently, which means the mattress responds locally to pressure rather than across the whole surface — a significant improvement over older open-coil designs.

Mattress Firmness Guide

Firmness is rated on a scale from 1 (very soft) to 10 (very firm), though most brands use descriptive terms. Your ideal firmness depends primarily on your sleeping position and body weight.

Best Mattress for Side Sleepers

Side sleeping is the most common position — and it places the most pressure on the shoulders and hips. If you wake up with a numb shoulder or sore hip, your mattress is almost certainly too firm for your sleeping style.

Side sleepers need a mattress that cushions the shoulder and hip while still keeping the spine in a neutral, straight line. A mattress that is too firm will leave gaps at the waist and create uneven pressure; one that is too soft will cause the shoulder to sink too deep and the spine to curve.

What to Look For

Choose a medium or medium-soft mattress (firmness 3–5) with a generous comfort layer of memory foam or latex on top. Look for a mattress with a spring count of at least 1,000 in a double size, and a comfort layer of at least 3–4cm of foam. Hybrid designs perform particularly well for side sleepers because the springs provide underlying support while the foam layer cushions pressure points precisely.

Best Mattress for Couples

Sharing a bed adds complexity to the buying decision. Two people rarely have identical sleep preferences, and one partner's movement can disturb the other all night long.

The most important feature for couples is low motion transfer. Memory foam and pocket spring hybrids excel here, because each pocket spring (and each foam cell) responds independently — meaning you won't feel every time your partner rolls over. Open-coil spring mattresses are the worst offenders for motion transfer and are best avoided for shared beds.

If you and your partner have significantly different firmness preferences, consider a zip-and-link mattress — two mattresses of different firmness zipped together as one — or a dual-tension pocket spring mattress where each side has a different spring tension. A super king (180 × 200 cm) is the recommended size for couples who want genuine space to sleep undisturbed.

Best Mattress for Children

Children's mattresses are often overlooked, but they matter enormously. A growing child spends more hours sleeping per day than an adult, and a supportive mattress aids proper spinal development.

For children under 12, opt for a medium-firm mattress rather than a soft one. Children are lighter and don't need as much cushioning as adults, and a firmer surface promotes better posture. Avoid very soft memory foam for young children. Pocket spring mattresses with a thin comfort layer are an excellent choice.

Look for mattresses with removable, washable covers — accidents happen. Hypoallergenic materials (natural latex, tightly woven fabrics) are also worth prioritising for children prone to allergies or asthma. A single mattress (90 × 190 cm) works well until the teenage years, when a small double may be worth considering.

How to Choose the Right Mattress: A Step-by-Step Guide

With hundreds of options available, the process can feel overwhelming. Break it down into five clear steps:

Step 1 — Know Your Budget

A quality double mattress starts at around £300–£500 in the UK, $400–$700 in the US, and €350–€600 in Europe. Mid-range options (£500–£1,200) represent the sweet spot for most buyers, offering good materials and construction without diminishing returns. Anything under £250 is likely to use low-density foam or open coils that will deteriorate quickly.

Step 2 — Identify Your Sleep Position

As covered in the firmness guide above, your sleeping position is the single most important factor in choosing firmness. If you sleep in multiple positions, choose medium (5–6) as your default.

Step 3 — Consider Health Conditions

Back pain sufferers generally benefit from medium-firm support with good lumbar support. Hip or shoulder pain responds best to pressure-relieving foam. If you run hot at night, look for gel memory foam or natural latex, both of which sleep cooler than standard foam.

Step 4 — Measure Your Room and Bed Frame

Always measure twice. Double-check that your bed frame matches standard dimensions if you're buying them separately. A double mattress (135 × 190 cm in the UK) will not fit a European double frame (140 × 200 cm) without an unsightly gap.

Step 5 — Use a Trial Period

Your body takes 2–4 weeks to fully adjust to a new mattress. Most reputable UK and US brands now offer a 100-night trial period. Don't buy a mattress from any brand that doesn't offer at least a 60-night in-home trial — you simply cannot judge comfort from a five-minute showroom test.

Do You Need a Mattress Topper for Your Double?

A mattress topper double is a layer of material — foam, latex, wool, or feather — placed on top of your existing mattress to alter its feel. It is not a replacement for a worn-out mattress, but it can meaningfully extend the life of a good one or fine-tune the comfort level.

Consider a topper if: your mattress is slightly too firm and you want to add softness; you're a side sleeper who needs extra cushioning on the shoulders and hips; or you share a bed and want to add a softer layer without replacing the whole mattress. A 3–4cm memory foam topper or a natural wool topper are the most popular choices for double beds in the UK.

Frequently Asked Questions