Small double mattresses

What size is a small double mattress?

A UK small double mattress is 120 cm wide and 190 cm long, which is 4ft x 6ft3. It's also sold as a 4ft or three-quarter mattress, and it sits between a single (90 cm wide) and a standard double (135 cm wide).

Watch out for that last row. A European small double is the same width but 10 cm longer, so it won't fit a UK 4ft frame, and a UK small double leaves a gap at the end of a European one. If your bed came from a European or flat-pack brand, measure the inside of the frame before you order. We list European small double mattresses separately so the two never get mixed up.

Is a small double big enough for two?

For the odd night, yes; for every night, most couples find it tight. Split down the middle, a small double gives each person 60 cm, which is 30 cm narrower than a single bed.

That's why small doubles suit one adult who likes room to stretch, teenagers moving up from a single, and spare rooms that see the occasional couple. If two of you will share every night, a double mattress gives 67.5 cm each and a king size mattress gives 75 cm each.

• Good fit: single adults, teenagers, guest rooms, box rooms and studio flats.
• Tight fit: two adults every night, or a couple whose youngest climbs in most nights.

Which type of small double mattress should I choose?

Choose by how you sleep. Memory foam suits side sleepers and light sleepers, pocket springs suit anyone who runs warm or needs firmer support, and hybrids sit in between.

• Memory foam: moulds around shoulders and hips, passes on very little movement and usually arrives rolled.
• Pocket sprung: springier, with air moving through the springs, and a good choice for heavier builds.
• Hybrid: pocket springs underneath with a foam comfort layer on top, for support and softness together.
• Open coil: lighter and cheaper, and fine for a guest room that's used a few times a year.

How firm should a small double mattress be?

Most people sleep well on a medium to medium-firm small double. Go softer if you sleep on your side, and firmer if you sleep on your front or are heavier, because more support stops the hips sinking.

Firmness isn't standardised between brands, so we grade every mattress on the same 1 to 10 scale on its product page. For a teenager who's still growing, medium to medium-firm is usually right: supportive without feeling hard.

How deep should a small double mattress be?

For an ordinary bed frame, 18 to 25 cm is typical. Deeper mattresses usually have more comfort layers, while slimmer ones suit day beds, guest beds and raised beds.

If your small double is going on a high sleeper or loft bed, find the maximum mattress line marked on the frame and choose a mattress at or below it, so the guard rail stays tall enough. Then check your fitted sheets: the pocket needs to be deeper than the mattress.

Will a small double mattress fit up my stairs?

Almost certainly, if you choose one that arrives rolled. Rolled mattresses come compressed in a box you can carry up a narrow staircase, then expand to full size within 24 to 72 hours.

Others arrive flat and fully wrapped, ready to sleep on straight away, and each mattress page tells you which. Most of our small doubles can be delivered the next working day; the delivery page has the details.

We're a family business, and we'd rather you ordered the right size first time. If you're not sure, measure the inside of your frame and send us the numbers. We'll tell you which size to order.

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