Sofa bed sizes explained: single, double and king

Sofa beds are sold by the number of seats, but you sleep on them by the mattress. That mismatch is why so many people end up with a “double” that two adults can’t share. Getting the sofa bed size right means looking at three numbers: the closed sofa, the sleeping surface and the full open footprint on your floor.

This guide explains the standard sizes in centimetres, how they compare with a normal UK bed, and how to check that the one you like actually fits your room.

Standard sofa bed sizes in the UK

There’s no strict standard, but most sofa beds sold in the UK fall into four bands. The table below shows typical sleeping surface sizes alongside a standard UK bed, so you can compare like with like.

Size	Typical sleeping surface	UK bed equivalent	Usually found on
Single	70 to 90cm wide, 180 to 190cm long	Single 90 x 190cm	Chair beds and futons
Small double	110 to 120cm wide, 180 to 190cm long	Small double 120 x 190cm	2 seater sofa beds
Double	130 to 140cm wide, 185 to 195cm long	Double 135 x 190cm	3 seater and corner sofa beds
King	150 to 160cm wide, 195 to 200cm long	King 150 x 200cm	Large corner and modular sofa beds

Notice the length. Plenty of sofa bed mattresses come in a few centimetres shorter than a normal bed, and anything under 185cm will feel cramped for anyone tall. If the listing gives a “190 cm” or longer sleeping length, that’s a good sign.

Single sofa beds and chair beds

A single sofa bed is usually a chair bed or a narrow futon. They’re brilliant for a home office or box room where a full sofa won’t fit, and for kids’ sleepovers. The catch is width. At 70 to 80cm many are narrower than a true single bed, so they suit children and smaller adults best.

The MAXYOYO folding sleeper chair below is a typical example: a chair by day and a floor-level single bed at night. Check the listing for exact dimensions, as these vary a lot between brands.

Small double vs double sofa bed size

This is where most buying mistakes happen. A small double sofa bed is roughly 120cm wide, which is fine for one adult with room to spread out, or a couple who don’t mind getting cosy for a night or two. A proper double sofa bed size is closer to 135 to 140cm, which matches a standard UK double bed.

As a rough rule, a 2 seater sofa bed opens to a small double and a 3 seater opens to a double. That’s not always true, though, so compare the sleeping surface measurement rather than the seat count.

The HOMCOM 2 seater is listed at 120cm, which puts it in compact, small double territory. The YODOLLA 2 seater is listed at 160cm wide as a sofa with a double pull-out section, so it gives you a wider bed for a similar closed footprint. Neither listing should be taken on trust alone, so check the open dimensions before you buy.

Is there a king size sofa bed?

Yes, but they’re rarer and bigger. A king size sofa bed is usually a large corner sofa bed or a modular sofa where several sections push together. You need a generous room for one, as the open footprint can easily pass 2.5 metres in one direction.

If you have the space, corner designs are the most practical way to get a king-ish sleeping area plus plenty of seating. Have a look at our corner sofa beds for options like the DURASPACE 275cm below.

The Bravich three-seater quotes 188 x 122cm on its listing, a handy example of why you should confirm whether a figure is the sofa or the bed. The DURASPACE is a 275cm modular corner, which gives you a lot of flexibility in how the pieces are arranged when someone stays over.

How much space do you need to open a sofa bed?

The closed sofa is only half the story. A pull-out sofa bed needs space in front for the mattress to unfold, while a click-clack stays roughly the same length and gets deeper instead. Here’s how to check your room:

• Measure the full open length from the wall, then add at least 50 to 60cm so people can walk round the end.
• Allow space either side for bedside tables or a lamp if guests will stay more than one night.
• Check the coffee table can be moved easily, or choose a footstool you can slide out of the way.
• Measure doorways, stairs and hallways too. Our guide to how to measure for a sofa walks you through it.

Mark the open footprint on the floor with masking tape. If you can walk round it comfortably, it’s the right fit for the room.

Choosing the right size for how you’ll use it

It really depends on how often it will be opened. For occasional guests, a small double is usually plenty and keeps the sofa compact in the living room. If two adults will share it regularly, or someone will sleep on it most nights, go for a full double with a deeper mattress. Our list of the best sofa beds in the UK covers both, and the sofa beds guide explains mechanisms and mattresses in more detail.

Don’t forget mattress depth. Two sofa beds with identical width and length can feel completely different if one has 8cm of foam and the other has 14cm with springs underneath. Thicker mattresses also add to the closed depth of the sofa, which matters in narrow rooms. If you can only fit a slim model, plan on adding a topper for guests.

Think about who will actually sleep on it, too. A teenager or a child will be fine on a single or small double for weeks at a time. Tall adults need length more than width, so check that sleeping length first. And if the sofa bed will live in a home office, a compact 2 seater that opens to a small double is often the sweet spot between floor space and comfort.

Storage is the other thing to weigh up. Some sofa beds and corner designs have a storage chaise or a drawer underneath, which is handy for guest bedding but usually adds to the overall size of the furniture. Whatever you choose, check the delivery details on the listing too, as larger sofa beds often come in more than one box and need assembling once they’re through the door.

You can browse every model we list in the sofa beds category and compare them side by side.

Sofa bed size FAQs

What size is a normal sofa bed?

A typical 3 seater sofa bed is around 190 to 210cm wide when closed and opens to a double sleeping surface of roughly 135 x 190cm. A 2 seater is usually 140 to 170cm wide and opens to a small double. Sizes vary, so always check the listing.

How wide is a double sofa bed?

A double sofa bed mattress is usually 130 to 140cm wide. Anything around 120cm is really a small double, even if it’s sold as a double. Measure the sleeping surface, not the sofa.

Which sofa bed is big enough for two adults?

Look for a sleeping surface of at least 135cm wide and 185cm long. A 3 seater pull-out or a corner sofa bed is the safest bet for two adults sleeping comfortably.

What is the typical size of a 3 seater sofa in metres?

Most 3 seater sofas are about 1.9 to 2.2 metres wide and 0.85 to 1 metre deep. Sofa bed versions tend to be at the deeper end of that range to house the mechanism.