UK Sofa Bed Sizes Guide: Dimensions, Mattress Depth & What Actually Fits

"Double" is a reassuring word. It suggests a bed for two adults, the same size as the one in your bedroom. The trouble is, when the word shows up on a sofa bed label, it almost never means the same thing.

Walk through the specifications of the major UK sofa bed retailers — from high-street names like DFS, John Lewis, and IKEA through to premium makers like Darlings of Chelsea — and a pattern emerges quickly. Mattresses are shorter than standard beds — usually 180 or 183cm against a real bed's 190 or 200cm. Mattresses are thinner — 10 to 14cm, not the 20–25cm of a proper mattress. And choice is narrow: most brands offer one or two widths, most capped around "double."

This guide breaks down sofa bed sizes across the UK, EU, and US, compares the major brands side by side, and explains why a few centimetres in length and a few more in mattress depth are the difference between "somewhere for guests" and "somewhere you'd choose to sleep."

Sofa Bed Sizes: UK, EU and US

Sofa bed sizing borrows from bed sizing, and bed sizing varies region by region. Before comparing what any sofa bed actually delivers, it helps to know what the labels should mean.

United Kingdom

Continental Europe

Continental European beds are commonly 200cm long. Widths mirror UK bed proportions but names differ — many retailers simply use the width in centimetres instead of words like "double" or "king."

Southern European countries (France, Spain, Italy) still use 190cm on older beds, with 200cm increasingly standard on newer ranges.

United States

The naming overlap is where the confusion starts. A US Queen is wider than a UK King. A "double" in Europe is larger than a "double" in the UK. And a "Queen" on a UK sofa bed often just means "small double." None of this matters until you buy a sofa bed based on the label and find it's 20cm shorter than your real one.

The Problem with Most Sofa Beds

Cross-check the sofa bed ranges at DFS, John Lewis, IKEA, and premium makers like Darlings of Chelsea against the bed size tables above, and four consistent problems appear.

1. They're shorter than real beds

DFS sofa bed mattresses are almost uniformly 180 or 183cm long. A standard UK single is 190cm, and a UK king is 200cm. That's a 10–20cm shortfall — enough that anyone over about 5'9" will hang their feet off the end. John Lewis's Cromwell measures 183cm; their Slumber range manages 196cm. IKEA's Friheten and Holmsund get closer to 200cm, at 199 and 201cm respectively, but remain shorter than a UK king or super king bed.

2. The mattresses are thin

Most high-street sofa bed mattresses are 10 or 11cm deep — roughly half the depth of a standard mattress. Premium makers like Darlings of Chelsea improve on this with 14cm pocket-sprung mattresses, a meaningful step up. But even that's still well below the 20–25cm of a dedicated bed. A thin pad folded around a metal mechanism is fine for the occasional guest, uncomfortable by night three, and can feel noticeably different to anyone used to their own mattress. Mattress depth is the single clearest indicator of whether a sofa bed is designed as a bed first, or as a sofa that happens to open.

3. Choice of size is narrow

IKEA's Friheten only opens to 144cm wide — somewhere between a UK small double and double. There is no single, no small double, no king, and no super king in the Friheten line. DFS sofa beds cluster around 110–115cm widths, mostly under the "2-seater" label. John Lewis has a handful of "large 3-seater" options that reach 132–140cm. Darlings of Chelsea offers a fuller range — 2-seater, 2.5-seater, 3-seater, and 3.5-seater — but the largest Helston and Bromley models still open to a UK-double-equivalent mattress. Nothing in the mainstream or premium offering approaches a UK king width of 150cm, let alone super king at 180cm.

4. The labels don't line up

A "double" sofa bed at DFS might be 112cm wide. A "double" at IKEA is 144cm. A "small double" at John Lewis can be 110cm when extended. None of these match a real UK double (135cm). The words carry meaning in bedroom furniture; on a sofa bed they become approximate at best. Always ignore the label and read the mattress dimensions.

Furl vs Typical UK Sofa Beds

This is the comparison that matters. For each UK bed size, here's what each of the major retailers actually offers — and whether the sofa bed matches the real bed dimensions.

Single (UK standard: 90 × 190cm)

Small Double (UK standard: 120 × 190cm)

Double (UK standard: 135 × 190cm)

King (UK standard: 150 × 200cm)

Super King (UK standard: 180 × 200cm)

Why 2 Metres Matters

The average adult man in the UK is 175cm tall. Add 10cm for a pillow and any natural posture, and 190cm is the realistic minimum for sleep without contorting. Over 6ft (183cm), 190cm is tight. A 180cm mattress is short for almost everyone.

There's also a question of how a bed feels. A 20cm shortfall isn't just a length problem — it means your feet either overhang or you curl up. Either way, you wake up differently. 200cm is the length that lets anyone up to about 6'6" sleep fully stretched out. That's not a generous size. That's a functional one.

Mattress depth matters too, for different reasons. A 10cm foam pad folded around a metal frame transmits every contour of the mechanism below. 18cm is the thickness at which the mattress, not the frame, decides how the bed feels. This is why Furl's sofa bed mattresses are 18cm deep and available in pocket spring, hybrid memory foam, and open spring — the same mattress technology you'd find in a dedicated bed.

The Furl Approach

Furl was founded to solve exactly the problem set out above. The starting point wasn't "design a sofa" but "design a bed that's also a sofa." The difference matters.

Every Furl sofa bed is built to the same specification:

• Five real bed sizes — single (80cm), small double (115cm), double (140cm), king (160cm), super king (180cm), not a 2/3/4-seater approximation
• Mattress length: 200cm across every size — longer than a UK standard single, small double, or double
• Mattress depth: 18cm — the minimum depth for genuine everyday sleep
• Mattress types: open spring, pocket spring, and pocket-spring-with-memory-foam hybrid — the same technology found in dedicated mattresses
• Designed for daily use — not "occasional" or "guest use," the standard caveat elsewhere

Our full sofa bed range includes the Metro, Tokyo, Cocoon, London, Paris, Piano, Mellow, Cambio, Swan, and Side by Side — each available in multiple widths, each built to the same bed-first spec.

How to Choose the Right Size

Start with daily use, not occasional

If the sofa bed will function as a spare bedroom — used every week or more — treat it as a bed first. Choose the size you'd pick if you were buying a real bed for that room. Occasional-use compromises compound fast when the sofa bed is actually used.

Measure for the open footprint, not closed

A sofa bed that fits as a sofa but blocks a doorway when opened is unusable. Measure your room with the bed extended and walked around. Allow 50–60cm clearance at the foot and at least one side. If the mechanism is a fold-out, check for the swing radius too.

Match the size to who actually sleeps there

A single is right for one person in a study or spare room. A small double works for one person with room to move, or two in a pinch. A double is the minimum for regular couple use. A king or super king on a sofa bed is a statement — available from Furl, essentially unavailable elsewhere — and makes sense if the room will be used as a proper guest suite.

Read the mattress spec, not the label

The words "double" or "2-seater" tell you very little. The numbers tell you everything. Look for width, length, and depth in centimetres, compare them to a real bed, and discount anything under 190cm long or under 12cm deep unless the sofa bed genuinely won't be slept on.