Double Sofa Bed UK: Sizes, What to Look For and the Best Models for Every Night

September 16, 2026

A double sofa bed is the size most people actually need: wide enough for two adults, small enough to live in a normal room. The problem is that the word "double" is used loosely. Some sofa beds sold as doubles open to a 120 cm small double, some to 135 cm, and the ones we make open to a 140 cm wide, 205 cm long mattress. This guide sets out what a double sofa bed measures in the UK, how it compares with small double and king size, what to look for if it will be slept on regularly, and which of the double sofa beds made by Sofa Bed Expert (sofabedexpert.co.uk) suit which room.

Short version: a true double sofa bed has a mattress at least 135 cm wide. Ours are 140 × 205 cm, wider and longer than a standard UK double bed, on a pocket sprung mattress built for every night. Prices start at £1,550 with free delivery and installation across England, Wales and Scotland.

What size is a double sofa bed?

A double sofa bed is a sofa that converts into a bed with a mattress of double width, which in the UK means at least 135 cm across. The National Bed Federation lists the standard UK double mattress as 135 cm wide by 190 cm long (4 ft 6 in by 6 ft 3 in). Sofa beds rarely copy that exactly. Because the bed is formed from the seat and back cushions rather than a separate mattress on a base, the width is set by the frame, and the length by how far the mechanism extends.

At Sofa Bed Expert we build the double sleeping area at 140 × 205 cm. The extra 5 cm of width gives two adults a little more room than a standard double, and the 205 cm length means anyone up to around 1.95 m tall sleeps without their feet touching the arm. That length is the single most useful number to check on any double sofa bed, because plenty of models on the market stop at 180 or 190 cm.

Double vs small double vs king size sofa bed

The three widths that matter are 120 cm (small double), 140 cm (double) and 150 cm (king). The differences look small on paper and feel large in use. A 120 cm small double is fine for one adult or a couple for a weekend. A 140 cm double is a comfortable every-night bed for two. A 150 cm king gives each person the same space as a standard UK single mattress. The table below compares the sizes as we build them, with the closed sofa width, because that is the number that decides whether it fits your wall.

One point worth noticing: the Oslo King Size is 170 cm wide closed, narrower than the 174 cm Millbrook 3 Double, yet it opens to a wider bed. That happens because the Oslo has slim metal legs and thinner arms. So if you are choosing on sofa width alone, do not assume the double is the compact option. Our sofa bed sizes guide lists every model with both measurements.

What to look for in a double sofa bed

Most disappointing sofa beds fail in the same three places: a thin foam mattress over a folding metal frame, a mechanism that is awkward to open every night, and a frame that was designed for occasional use. Here is what to check before you buy, whether from us or anyone else.

1. Pocket springs, not just foam

A pocket sprung sofa bed has hundreds of individual springs, each in its own fabric pocket, inside both the seat and the mattress. They compress independently, so the surface follows your body instead of sagging into a dip. Every double sofa bed we sell uses pocket springs in the seat and the mattress, combined with zig-zag springs in the base and high resilience foam. That is the same construction principle as a good divan mattress, which is why our sofa beds are described as every-night beds rather than guest beds. We explain the mattress types in detail in foam vs sprung vs pocket sprung.

2. A mechanism you will use daily

Our double sofa beds use a pull-out system: the seat slides forward and the back folds down to make a flat bed in one movement, no cushions to remove and nothing to lift over your head. It takes a few seconds and can be done by one person. For a bed that is opened once a month a heavier mechanism is tolerable; for a bed that is opened every night it is the difference between using the sofa bed and sleeping on the sofa.

3. Frame and weight capacity

Ask for a stated weight capacity. A frame built for occasional use often has none. Our Millbrook frames are flexible plywood, rated to 250 kg, which is the load of two adults with room to spare. Cushions are silicone fibre filled so they recover their shape rather than flattening within a year.

4. Bed length

Check the length as carefully as the width. A 140 cm wide bed that is only 180 cm long is a double for people under 1.75 m. Ours are 205 cm long on the Millbrook range, and 200 cm on the Nap and the Mocca corner models.

5. Fabric that survives daily use

A sofa bed that is slept on every night is also sat on every day, so the fabric takes twice the wear of a normal sofa. All our fabrics are flame retardant to the UK Furniture and Furnishings (Fire) (Safety) Regulations 1988, breathable and stain resistant, and we send free samples so you can test them at home. See the fabric collections and our cleaning guide.

6. Storage, if the room is small

A double sofa bed with storage adds a compartment under the seat for the duvet, pillows and a fitted sheet, so the bedding lives with the bed. It costs a little more and adds about 26 cm to the sofa width, which is why we make the double in both versions.

Our double sofa beds compared

We make two double sofa beds and two small doubles. All four share the same pocket sprung construction, the same fabric ranges and the same delivery service, so the choice comes down to width, storage and how often two adults will share it.

Millbrook 3 Double, £1,550. The straightforward choice. At 174 cm wide it is a normal three-seater sofa that happens to open into a bed wider and longer than a standard double. It is the model we recommend most often for guest rooms and for living rooms where the sofa bed is used a few nights a week.

Millbrook 3 Double Storage, £1,699. The same bed with a storage compartment under the seat and a wider, 200 cm frame. This is the one for studio flats and spare rooms where there is no wardrobe space for bedding. It is also sold as a bundle with a matching storage footstool at £1,599, which is currently cheaper than the sofa bed alone because the bundle is on offer.

Which double sofa bed for which room

Guest room used a few times a month: Millbrook 3 Double. Guests get a bed that is wider than the double in most hotel rooms, and the sofa is comfortable enough to make the room usable the rest of the time.

Living room, slept on most nights: Millbrook 3 Double if one person sleeps on it, Millbrook 3 Double Storage if you need somewhere for the bedding, and honestly a king size (Oslo or Millbrook King Size) if two adults share it every night. The extra 10 cm is worth £100 to £150 over the years you will own it.

Studio flat or small spare room: Millbrook 3 Double Storage, or the 154 cm wide Millbrook 2 Compact if the wall is short. Measure the room with the bed open: you need the sofa depth of 96 cm plus roughly 110 cm in front of it for the bed to extend.

Corner of the room: a double is not the only shape. The Tampa Corner Storage opens to 120 × 205 cm with storage, and the Mocca King Size Corner to 150 × 200 cm. Our left or right hand facing guide explains how to choose the orientation.

Delivery, returns and trying one first

Every double sofa bed is made to order in your choice of fabric. Production takes around 2 weeks, and about 95% of orders are delivered within 18 to 21 days of ordering. Delivery is free across England, Wales and Scotland, carried out by our own two-person team who bring the sofa bed into the room you choose, install it and take the packaging away. Because the Millbrook range is built to pass through a 48 cm gap, tight hallways and flats are rarely a problem; our delivery access guide has the measurements.

You can cancel at any time before delivery for a full refund, and you have 14 days after delivery to return or exchange, with free collection by our own team. If you would rather sit and lie on one first, our showroom in Bognor Regis has the double and king size models set up as beds.

Frequently asked questions

What size is a double sofa bed in the UK?

A double sofa bed opens to a mattress at least 135 cm wide, the standard UK double width. Sofa Bed Expert double sofa beds open to 140 × 205 cm, which is 5 cm wider and 15 cm longer than a standard UK double bed of 135 × 190 cm. Closed, the sofa is 174 cm wide, or 200 cm for the storage version.

Is a double sofa bed big enough for two adults every night?

Yes, provided the mattress is a true double of 135 to 140 cm and is pocket sprung rather than thin foam. A 140 cm wide bed gives two adults comfortable room. If two people will share it every single night, a 150 cm king size sofa bed adds noticeably more space for around £100 more.

What is the difference between a small double and a double sofa bed?

A small double sofa bed opens to a 120 cm wide mattress, a double to 135 to 140 cm. The 20 cm difference is the width of a pillow. Small doubles suit one adult or occasional couples and fit a 154 cm wall; doubles suit two adults regularly and need around 174 cm of wall.

How much does a double sofa bed cost?

A pocket sprung double sofa bed built for every-night use costs from £1,550 at Sofa Bed Expert, or £1,699 with built-in storage, including free delivery and installation across England, Wales and Scotland. Cheaper sofa beds usually use foam over a metal frame and are intended for occasional guests.

Can I get a double sofa bed with storage?

Yes. The Millbrook 3 Double Storage Sofa Bed has a compartment under the seat large enough for a duvet, pillows and a fitted sheet. It opens to the same 140 × 205 cm bed as the standard Millbrook 3 Double and is 200 cm wide closed rather than 174 cm.

How long does a double sofa bed take to deliver?

Sofa Bed Expert double sofa beds are made to order in around 2 weeks, and 95% of orders are delivered within 18 to 21 days of ordering, by the company's own two-person team, free of charge across England, Wales and Scotland.

---

Also in Sofa Bed