Sofa Bed Sizing Guide: Dimensions for Every Space

A standard 2-seater sofa bed measures roughly 150-180cm wide when folded and unfolds to a small double or double bed (120-135cm wide, 190cm long). A 3-seater sofa bed measures 200-230cm wide folded and unfolds to a double or king-size bed. The right size for you depends on the room dimensions, doorway width, and how often the sofa bed will be slept on.

Key Takeaways

• Sofa bed dimensions vary significantly, from armchair-sized options for studios to 3-seaters that unfold to a king-size sleeping surface.

• Measure both your room and your doorways before buying. A sofa bed that fits the room but not through the front door is one of the most common regrets in this category.

• Allow at least 60-75cm clearance in front of the sofa bed for it to unfold, plus room to walk around it.

• UK sofa bed mattress sizes follow standard bed dimensions: single (90 x 190cm), small double (120 x 190cm), double (135 x 190cm), and king (150 x 200cm).

• Check the folded footprint and the unfolded footprint separately. A compact sofa can unfold to a surprisingly large bed, and a large-looking sofa can hide a modest sleeping surface.

Standard Sofa Bed Dimensions (Folded vs Unfolded)

Sofa beds have two footprints: the sofa footprint (what the piece occupies day-to-day) and the bed footprint (what it needs when unfolded). Both matter for room planning.

Sofa footprint (folded, everyday use):

Bed footprint (unfolded, sleeping use):

The unfolded length typically extends 60-80cm beyond the folded depth of the sofa. So a sofa that sits 95cm from the wall will need roughly 200cm of floor space in front of it when the bed is out. Always plan for the unfolded footprint, not just the folded one.

How to Measure Your Room Before You Buy

Getting the size right is the single biggest thing you can do to avoid an expensive return. Take these six measurements before you shop.

• Measure the Sofa Space Width

Measure the full width of the wall or floor space where the sofa will sit, including any obstructions like radiators, skirting boards, or plug sockets. Add at least 10cm of clearance on each side for airflow and access.

• Measure the Wall-to-Obstacle Depth

Measure the depth from the wall to any obstacle in front of where the sofa will sit. This is where the unfolded bed will extend when you use the sleeping function. Coffee tables, TV units, and rugs all count.

• Mark the Unfolded Footprint on the Floor

Use masking tape to mark out the sofa bed's unfolded dimensions on the floor: typically 135 x 200cm for a 2-seater, 150 x 210cm for a 3-seater including frame. Walk around the taped area to check clearance. If you can't comfortably walk past the marked footprint, the sofa bed is too large for the room.

• Measure Every Doorway Width and Height

Measure every doorway the sofa bed needs to pass through, from the front door to the destination room. Include the height, because taller sofa beds sometimes need to be tilted to fit. A sofa bed that fits the room but not through the door is one of the most common regrets in this category.

• Check Staircases, Landings, and Corridors

Note any narrow turns, sharp corners, or low ceilings along the delivery path. A sofa bed that fits through a doorway but not around a landing turn is a common obstacle in older UK properties. Measure the tightest point on the route, not the widest.

• Measure the Lift Dimensions

If you're in a flat, measure the lift interior height, width, and depth. If the lift can't take the sofa bed flat or on its end, you'll need a delivery team who can handle stairs, which affects both cost and scheduling.

Compare each measurement against the "packaged dimensions" given by the retailer, not just the assembled sofa bed size. Delivery boxes are usually a bit larger than the finished product.

Sofa Bed Sizes by Seat Count

Choosing the right seat count depends on how the sofa bed will be used, the room it's going in, and who's most likely to sleep on it.

1-Seater / Armchair Sofa Beds

Sofa dimensions: roughly 90-110cm wide, 90-100cm deep. Bed dimensions: single (90 x 190cm).

Best suited to studios, home offices that occasionally host guests, and children's rooms. The compact footprint means the piece works as an armchair during the day without dominating the room, and unfolds to a proper single bed for one guest. Not suitable for two adults sharing.

2-Seater Sofa Beds

Sofa dimensions: roughly 150-180cm wide, 90-100cm deep. Bed dimensions: small double (120 x 190cm) or double (135 x 190cm).

The most common choice for UK flats and small living rooms. Comfortable for two people sitting, and unfolds to a bed that accommodates one adult in comfort or a couple in a pinch. Works well for occasional overnight guests, weekend visitors, or a spare-room alternative.

3-Seater Sofa Beds

Sofa dimensions: roughly 200-230cm wide, 90-100cm deep. Bed dimensions: double (135 x 190cm) or king (150 x 200cm).

Suited to larger living rooms, family households, and homes that host regular overnight guests. The generous sofa proportions handle everyday use for three, and the unfolded bed is comparable in size to a proper spare bed. Best option if the sofa bed will be slept on more than a few nights per month, or by a couple sharing.

For a deeper look at how our range fits each seat-count category, see our Space-Saving Sofa Bed, Designer Sofa Bed, and Sofa Bed for Families landing pages, each framed for a different use case.

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Our Koala Sofa Bed Range

Our Koala Sofa Bed is designed for the reality of UK living: flats and terraced houses where the sofa needs to fit through narrow hallways, adapt to occasional overnight guests, and hold up across moves between homes. It works as a proper sofa and a proper bed, without the compromise older sofa beds forced on either side.

Three ways to look at the same sofa bed depending on what you're solving for:

• Koala Space-Saving Sofa Bed for smaller flats and studios where every square metre counts.

• Koala Designer Sofa Bed for living rooms that need a sofa bed that looks intentional, not like a compromise.

• Koala Sofa Bed for Families for households with kids, guests, and the everyday wear that comes with both.

All three sit on the same piece of furniture, engineered in-house for repeated use across the lifespan of a UK renter's or homeowner's furniture cycle. Measure your room first, then work out which framing fits your situation.

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FAQs

What size is a standard sofa bed mattress?

Standard sofa bed mattress sizes in the UK match the country's bed size conventions: single (90 x 190cm), small double (120 x 190cm), double (135 x 190cm), and king (150 x 200cm). Most 2-seater sofa beds unfold to a small double or double, and most 3-seater sofa beds unfold to a double or king. Sofa bed mattresses are typically slightly thinner than dedicated bed mattresses (10-15cm compared with 20-30cm), because the mattress has to fold inside the sofa frame.

How much floor space do I need to open a sofa bed?

Plan for at least 60-75cm of clear floor space in front of the sofa bed to unfold it, plus enough room to walk around the bed once it's open. In practice, that means most 2-seater sofa beds need roughly 135 x 200cm of floor space when unfolded, and most 3-seater sofa beds need 150 x 210cm or more. Use masking tape to mark out the unfolded footprint on your floor before ordering; it's the reliable way to know whether the space actually works.