A sofa set is usually described in numbers: 3+2+1, 3+3, 3+2, or a corner sofa plus an armchair. The numbers count the seats per piece, and each combination suits a different room shape, a different way of sitting together and a different amount of floor space. Choosing the configuration before the model saves a lot of measuring and second-guessing later.
This guide goes through the common combinations, the room sizes they typically need and how to arrange them so people can talk without turning their heads. The figures below are general guidance. At Sitdesign, custom dimensions are available on request when a standard model is a few centimetres off for your room.
Start with three measurements
Before comparing layouts, draw the room on paper and mark three things:
- Walkways. A main route through the room typically needs 80–90 cm of clear space; a secondary path behind a sofa can be 60–70 cm.
- The focal point. A fireplace, a window with a view or a TV wall decides which way the main sofa faces.
- The conversation circle. People sitting opposite each other talk comfortably at roughly 2.4–3 m apart. Beyond about 3.5 m the group starts to feel split.
As a rough guide, a three-seat sofa is 200–240 cm wide, a two-seat sofa 150–180 cm and an armchair 80–100 cm. Most sofas are 90–105 cm deep. Leave 40–45 cm between the front of the seat and the coffee table so that both knees and hands reach it comfortably.
3+2+1: the flexible classic
A three-seat sofa, a two-seat sofa and an armchair seat six people and form an open square around a coffee table. This works well in rectangular living rooms of about 20–30 m²: the three-seater faces the focal point, the two-seater stands at a right angle along the side wall, and the armchair closes the group opposite the two-seater or angles in from the open corner.
The main advantage is flexibility. The pieces can be moved apart later, and the armchair is easy to shift when guests arrive. Keep the seat heights within a centimetre or two of each other (typically 42–46 cm) so the group feels level. Many people choose both sofas in one model from our sofa collection, such as the Platon sofa, and add a contrasting armchair like the Oscar armchair so the set looks planned rather than simply matched.
In smaller rooms of 15–20 m², a 3+2 without the armchair is the practical version. In a narrow room, a single three-seater with two armchairs opposite (3+1+1) often works better than two sofas, because armchairs need less wall length and can turn slightly towards each other.
3+3: two facing sofas
Two three-seat sofas facing each other across a long coffee table give the most symmetrical and formal layout. It suits rooms where the focal point sits at the end of the group rather than in front of it: a fireplace on the short wall, a large window, or a living room where the TV is not part of the plan.
This layout needs width more than length. Two sofas of about 100 cm depth plus a table zone of about 130 cm make the group roughly 3.3 m deep, so the room should be at least 4.5 m wide to keep a walkway on one side. Facing sofas also work as a divider in open-plan spaces, with a console behind one of them. One or two armchairs at the open end turn a 3+3 into a group for eight.
Corner sofas: L-shaped and U-shaped
A corner sofa uses the corner of the room, which a 3+2+1 set leaves empty. In rooms of 15–20 m², an L-shaped sofa often seats more people on less floor area than separate pieces, and the corner gives one deep position for lounging. In open-plan rooms, the back of the L marks out the living area without a wall.
Two points matter when choosing one:
- Left or right. The side of the longer arm is usually described as seen when you stand facing the sofa. Check it against doors and windows on your plan before ordering.
- Arm lengths. The longer arm should face the focal point; the shorter arm closes the group. Very long arms, over about 3 m, push the far seats out of the conversation circle.
A model such as the Charlie corner sectional sofa works well with one armchair placed opposite the short arm, which completes the circle without blocking the walkway. A U-shaped arrangement seats more people but needs a room at least 4 m wide, with the open side facing the focal point.
The coffee table holds the set together
A common rule is to choose a coffee table about two-thirds the length of the main sofa, and 35–45 cm high, slightly below the seat. For 3+2+1 and corner layouts, a square or round table, or a set of two or three tables such as the Monica coffee table set, reaches every seat more easily than one long rectangle. For facing sofas, a long rectangular table keeps the symmetry.
The circulation around the group matters as much as the pieces themselves. For more on this, see our article on how circulation patterns influence furniture placement.
Materials across the set
Upholstering every piece in the same leather gives a calm, unified look; a different colour or a fabric on the armchair adds contrast without breaking the set. Sitdesign works with genuine leather only, in 76 colours across 12 colour families, with Italian leathers forming our top leather group. Fabric upholstery is also possible, and we accept customer's own material (COM).
Whatever the configuration, the construction is the same: frames in kiln-dried beech, high-resilience (HR) foam with sprung seating, and every piece handmade in our own factory in Büyükçekmece, Istanbul.
Send us your room measurements and the configuration you have in mind, and we will prepare a quote and send leather samples on request. Contact us here.
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