How to Measure Up for Double Sofa Beds: A Simple Sizing Guide

To measure up for a double sofa bed, you need four numbers: the closed footprint (width and depth), the fully open length, the clear floor space in front of where the sofa will sit, and the narrowest point on the route into the room. A standard UK double mattress is 135 cm wide and 190 cm long, so a double sofa bed will usually open to roughly that size, and the full open length including the sofa back is typically longer. Add space to walk around the open bed and you have the number that really matters.

That sounds simple, and it is, once you know what to look for on a product page and which corners of your room to check. This guide takes you through each measurement in order, with practical tips for the awkward spots that catch people out. When you are ready to compare designs, our full range of double sofa beds UK lists dimensions for each model so you can check them against your notes.

What you need before you start

Gather a metal tape measure, a notepad or your phone, a roll of masking tape and, if possible, a second person to hold the other end of the tape. A metal tape is more accurate than a fabric one over longer distances. Write every number down as you go, in centimetres, and label each one clearly so you do not mix up width and depth later.

Step one: understand the dimensions on a product page

Most sofa bed listings give at least five figures. Knowing what each one means will save you a return trip.

• Width: the measurement from the outside of one arm to the outside of the other.
• Depth: the distance from the very back of the frame to the front edge of the seat, when closed.
• Height: from the floor to the highest point of the back.
• Open length: the total distance from the back of the sofa to the foot of the opened bed.
• Sleeping area: the mattress size itself, usually close to the standard double.

Some listings also include seat height, seat depth and arm height, which help you judge comfort. The open length is the figure people most often overlook, yet it is the one that decides whether your bed will fit between the sofa and the opposite wall. If you are deciding between a sofa bed and a standard sofa for the same wall, our modern sofas UK sale collection lists closed dimensions for fixed designs too, which makes side by side comparison simple.

Step two: measure the wall

Measure the length of the wall where the sofa bed will sit, from corner to corner or from corner to the edge of any obstacle. Note the positions of radiators, sockets, windows, doors and skirting heating. A radiator does not stop you placing a sofa bed against it, but you will want a gap of a few centimetres for air to circulate, and a click clack design will need extra room behind it to fold flat.

Leave a little breathing space either side of the sofa. A frame that fits a wall exactly can look cramped and make it awkward to tuck in bedding. A margin of around 10 to 20 cm on each side is a comfortable rule of thumb in most rooms.

Step three: measure the floor in front

This is the critical measurement. Stand with your back to the wall where the sofa will sit and measure straight out to the opposite wall or the nearest fixed object, such as a wardrobe, a built in cupboard or a fireplace hearth. Write this down as your clear floor length.

Compare it with the open length of the sofa bed you like. Then add room to move. You will want enough space at the foot of the bed for a guest to walk past, and ideally space along at least one side to get in and out without climbing over the mattress. Around 60 cm is a comfortable walkway in most homes, though a little less can work in a box room that will only be used occasionally.

Step four: check doors, windows and furniture

With the open footprint in mind, look at everything that swings or moves in that space:

• Does the room door open inwards across the area the bed will occupy?
• Can wardrobe doors and drawers still open when the bed is out?
• Will curtains or blinds be blocked?
• Is there a radiator valve or pipe at floor level that the frame might catch?

Furniture you can move easily helps a great deal. A heavy coffee table that has to be dragged aside every time you open the bed becomes a chore. A set of nesting tables or a small side table is far easier. Our modern nest of tables UK range is worth a look if you want surfaces that tuck away neatly when the bed comes out.

Step five: mark it out with masking tape

Numbers on paper rarely tell the whole story. Use masking tape to mark the closed footprint of the sofa on the floor, then a second outline for the open bed. Leave the tape down for a day or two and walk around it. You will quickly notice if the room feels tight, if a door clips the corner, or if the walkway to the window is too narrow.

This step is particularly useful in rooms that already have furniture. You can see how the open bed sits next to a desk, a chest of drawers or a bookcase, and decide whether anything needs to move.

Step six: measure the route in

Many sofa bed problems happen before the piece reaches the room. Measure every doorway along the delivery route, including the front door, internal doors and any porch. Measure the width of the hallway, the width of the staircase, and the height of any ceiling that drops over the stairs.

The figure to compare against is the diagonal depth of the sofa. If a doorway is narrower than the closed depth but wider than the diagonal, the sofa can usually be tilted through. Turns on stairs and tight landings are the most common sticking points, so check the space at each turn carefully. Removable feet can save a few useful centimetres.

Step seven: think about height and headroom

In loft rooms and spaces under the eaves, the height of the open bed matters. Guests need enough headroom to sit up comfortably. Check the ceiling height where the head of the bed will be, not just in the centre of the room. A low profile sofa bed or a design that opens away from the slope can make a room under the roof far more usable.

Small double or double: which do you need?

A small double is 120 cm wide, while a standard double is 135 cm. Both are typically 190 cm long. A small double can suit single guests, older children or a narrow room. A double is the safer choice if couples will stay. If you regularly host taller visitors, check that the open sleeping length is generous, because some sofa bed mattresses are slightly shorter than a standard bed mattress.

Mattress depth matters for comfort as much as width. A deeper mattress gives a more bedlike feel. If you are considering upgrading the mattress later, check the depth allowance in the frame and browse our mattresses UK sale section to compare options. You may also find our explainer on memory foam sofa bed mattresses in UK homes helpful when weighing up comfort.

Common measuring mistakes

• Measuring the mattress size and forgetting the sofa back adds to the open length.
• Forgetting skirting boards, which push the sofa a few centimetres away from the wall.
• Ignoring the radiator gap, especially with click clack designs.
• Assuming a door can stay open when it actually swings into the bed area.
• Checking the room but not the staircase or front door.
• Rounding numbers down. Always round up when measuring your room and down when reading the product dimensions, to give yourself margin.

Putting your numbers together

Once you have your measurements, list them in a simple table on your phone: wall length, clear floor length, narrowest doorway, staircase width and ceiling height. Next to each, note the matching figure from the sofa bed listing. If every room number comfortably exceeds the product number, you are in good shape. If one is close, go back and remeasure that point, and consider whether a different mechanism or a smaller frame would give you more room. Our separate guide to sofa bed open dimensions for UK rooms is a useful companion when you get to this stage.

When you are ready to choose, browse the range at Furniture in Fashion, where every listing includes full dimensions and we offer free delivery to most UK mainland postcodes.

Frequently asked questions

How much space do I need in front of a double sofa bed?

You need the full open length of the bed measured from the wall, plus a comfortable walkway at the foot. Check the open length on the product listing, as it varies by mechanism.

Is a double sofa bed the same size as a double bed?

The sleeping area is usually close to a standard UK double of 135 by 190 cm, but always check the listing, as some mattresses are slightly smaller.

Do I need to leave a gap behind a sofa bed?

For pull out designs, a small gap for skirting and radiators is enough. Click clack designs need extra space behind so the back can fold down flat.

What if my staircase is too narrow?

Compare the diagonal depth of the sofa with the narrowest point on the stairs. Designs with removable feet or arms can help on tight routes.