Mattress toppers

What does a mattress topper do?

A mattress topper changes how a mattress feels, usually making it softer, by adding a removable layer of foam, fibre or another filling on top.

A topper is most useful on a mattress that's in good condition but feels too firm: a new mattress that's firmer than you expected, a guest bed, or a rented or student bed you can't replace. A side sleeper on a firm mattress may find that a soft topper lets the shoulder and hip sink in a little further. What a topper can't do is change the support underneath. It also adds height, which matters for fitted sheets and raised beds.

Can a mattress topper fix a sagging mattress?

A mattress topper can't fix a sagging mattress, because a topper follows the shape of whatever is underneath it, dip included.

If your mattress sags, has lumps, has springs you can feel or leaves you waking up stiff, it's due for replacing rather than covering. An adult mattress typically lasts around 7 to 10 years. Check the base before you blame the mattress, though: broken or widely spaced slats can make a sound mattress dip. If you are replacing it and a softer feel is what you're after, start with our soft mattresses.

Memory foam or fibre topper: which is better?

Choose a memory foam topper if you want a bed to feel softer and mould around you, and a fibre topper if you want a lighter, quilted softness that's easier to lift and often easier to wash.

Memory foam was developed in the 1960s from NASA-funded research, and it's the material to choose for a slow, sink-in feel. If you like that feel enough to want it all the way through, our memory foam mattresses combine it with a supportive base.

How thick should a mattress topper be?

A mattress topper should be only as thick as the change you need: a thinner topper takes the edge off a firm mattress, while a deeper one changes the feel more but raises the bed further.

• Thinner toppers soften the surface a little and add little height, so your existing sheets are more likely to fit.
• Deeper toppers make a bigger difference to the feel, but need a fitted sheet and protector with a pocket deeper than the mattress and topper together.
• On a raised bed, any topper counts towards the depth limit, so read the next section first.

To stop a topper sliding, look for elastic corner straps or a fitted skirt, and put the fitted sheet over the mattress and topper together.

Can you put a mattress topper on a bunk bed?

You can put a mattress topper on a bottom bunk, but on a top bunk, high sleeper or cabin bed the mattress and topper together must stay at or below the maximum mattress line, and on most top bunks there's no room for one.

Under BS EN 747, the line marks the highest the sleeping surface can sit while leaving at least 16 cm of guard rail above it. Many raised beds take a mattress no deeper than 15 to 16 cm, and a topper lifts the surface just as a deeper mattress would. If a child finds a top bunk mattress too firm, a softer slim mattress is a safer fix than a topper. For more on finding and measuring the line, see our bunk bed mattresses and high sleeper mattresses.

A new topper can change how high your shoulder sits, so check your pillow still suits the way you sleep, and put a mattress protector over the top to keep the topper clean. If you're weighing a topper against a new mattress, tell us about your bed and we'll give you an honest view.

Written by the Mattress Town team. Last updated 9 October 2026.