Choosing sofa dimensions for your room

Work out the longest and deepest sofa your room can take, with a worked example covering wall length, depth, the coffee-table gap and walking space.

The sofa is usually the largest object in a living room, and the hardest to return. Before you compare fabrics, work out the maximum length and depth your room can take. The method below needs only your room measurements and a few decisions about how you want to move through the space.

Step by step

Choose the wall or position. Note the usable length: wall length minus anything that interrupts it, such as a door frame, radiator or window you do not want to cover.
Decide what shares that wall. Side tables, a floor lamp or a gap for curtains all subtract from the length available.
Add up the depth across the room. From the sofa wall outward: sofa depth, the gap to the coffee table, the table itself, the walking space beyond it, and whatever stands on the opposite wall.
Check seat depth separately. Overall depth includes the back cushions and frame. Seat depth, which determines comfort, is a different number on the product page.
Draw it. Add a sofa in the Room Planner, type the product’s real width and depth, and look at the distances shown when you select it.

Starting points, not rules. Many people find a gap of about 40–50 cm (16–20 in) between sofa and coffee table comfortable to reach across and step through, and prefer main walking routes of roughly 75–90 cm (30–36 in). These are common planning suggestions only. Choose what suits your household, and treat any accessibility need as its own requirement.

Add the depths across the room. Whatever is left over is your walkway.

Worked example

The room is 360 cm wide and 420 cm long. The sofa will stand on a 420 cm wall, but a door takes the last 100 cm, leaving 320 cm usable. You want a 45 cm side table at one end and at least 20 cm free at the other so the sofa does not touch the door frame.

Length: 320 − 45 − 20 = 255 cm. A 215 cm three-seat sofa fits with 40 cm to spare; a 260 cm sofa does not.

Depth: across the 360 cm width you plan a 92 cm deep sofa, a 48 cm gap, a 60 cm coffee table and a 40 cm TV unit. 92 + 48 + 60 + 40 = 240 cm, leaving 360 − 240 = 120 cm between the coffee table and the TV unit. If you chose a 105 cm deep sofa instead, the walkway would drop to 107 cm. The “Small living room” example in the planner uses these same depths, so you can open it and try other sizes.

Sectionals and corner sofas

An L-shaped sofa needs two wall lengths. Check which end the chaise is on (“left-hand” and “right-hand” are named differently by different retailers, so rely on the diagram). In the planner, use “Sectional sofa (L-shape)”, type both overall lengths and the cut-out size, and use Mirror to switch sides.

Common mistakes

Measuring only the wall and forgetting the depth across the room.
Forgetting the sofa must also get into the room. See checking doorways and delivery routes.
Blocking a radiator or covering a low window sill with a high back.

Limits

A plan cannot tell you whether a sofa is comfortable or whether its proportions suit the room’s height. If you can, sit on it in a showroom and tape its outline on your floor at home.

Try sofa sizes in the Room Planner

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