Silentnight Deep Sleep Ultimate 500 Mattress Topper im Test

The Silentnight Deep Sleep Ultimate 500 Mattress Topper is a 5cm quilted topper with a hypoallergenic fibre filling held in place by internal walls, sold in four UK sizes from £32 for a single at its regular price. It is the slimmer sibling of the 10cm Deep Sleep Ultimate 1000.

Construction

The Silentnight product page describes a luxuriously soft quilted cover with internal walls that stop the filling drifting to the edges, which is the usual failure of cheap fibre toppers. Corner straps hold it on the mattress.

Feel

At 5cm, this one softens gently rather than transforming the bed; we rate the feel medium-soft, 4 out of 10.

If you buy it for allergies, the fibre is hypoallergenic, but Allergy UK advises washing bedding at 60°C or above to kill dust mites, so check the care label.

Sizes and prices

These are regular prices, checked in September 2026. At the time of writing Silentnight had it on an autumn offer from £32, with no end date. Silentnight’s dimension table gives king and super king as 220 x 225cm and 220 x 260cm, which do not match the bed sizes, so rely on the size names. Delivery takes 2 to 3 working days and there is a 2-year guarantee.

500 or 1000?

The difference between the two Deep Sleep Ultimate toppers is depth: 5cm here and 10cm in the 1000. In a single the 500 costs £32 at its regular price and the 1000 costs £37, so the deeper model is barely more expensive. Choose the 500 if you want to take the edge off a mattress that is only slightly firm, or if you need a topper that keeps the bed height close to what your fitted sheets already cover. For a real softening effect, the 1000 is the better buy.

At 5cm it adds little height, so your existing fitted sheets will usually still fit. Silentnight does not sell it as waterproof, so use a mattress protector over the topper if spills are a risk.