Sofa Buying Guide: Size, Seating & Modular Configurations
A sofa is one of the largest and longest-kept pieces in a home, so it's worth thinking through a few practical questions before you buy — how many people it really needs to seat, whether a fixed or modular design suits your room, and how the configuration you choose affects the amount of floor space required. This guide walks through those decisions, with real examples from Voyager's range.
Fixed or Modular — What Suits You?
A fixed sofa is a single, set piece — simplest to place and live with, and a good fit where the room has one clear, settled spot for it.
A modular sofa is built from individual seating modules that can be arranged in different layouts — straight, chaise, corner or, in some designs, curved. The advantage isn't just style: a modular sofa can be reconfigured if you move house, rearrange a room, or want a different layout for entertaining versus everyday use. Ditre Italia's Pacific Sofa and Atlantis Sofa, and Amura's Lapis Sofa, are examples of modular designs in our range. Browse the full sofa collection to see fixed and modular options side by side.
How Many Seats Do You Actually Need?
It's easy to size a sofa for the biggest gathering you can imagine rather than how the household actually uses it day to day. As a general guide, allow roughly 55–60cm of seat width per person — so a 3-seat sofa is typically comfortable for three adults sitting normally, not squeezed in. If you regularly need to seat six or more people, it's often more practical to reach that capacity through a modular or corner configuration, or a sofa plus a couple of armchairs, rather than a single very long straight sofa that may not fit the room. This is general guidance rather than a fixed rule — actual comfortable capacity depends on the specific design, cushion depth and how snugly your household likes to sit.
Straight, Chaise or Corner
A straight sofa has the simplest footprint and is easiest to place against a single wall. A chaise configuration extends one end into a longer lounging section — good for stretching out, and often used as a practical alternative to a separate armchair or ottoman. A corner configuration wraps around an angle of the room, which can seat more people in a more compact overall footprint than an equivalent straight sofa, and suits open-plan living and dining areas well. Ditre Italia's Atlantis Sofa is a modular system built around variable seating depths and tilt-adjustable module angles, illustrating how a single modular collection can be arranged into quite different shapes and comfort levels depending on the room it's going into.
How Modular Configurations Change the Footprint
The same modules, arranged differently, can produce quite different overall shapes and floor space requirements. The images below show Amura's Lapis Sofa from above in two configurations — a straight-and-corner layout, and the round Lapis Round Sofa arranged as a sweeping curve — illustrating how configuration changes the footprint even within the same design family.
Before settling on a configuration, it's worth roughly mapping the modules against your room — a corner or curved layout can seat comfortably in a footprint that a straight sofa of similar capacity wouldn't fit into, but it also needs clear wall or floor space along two directions rather than one.
Sofa Depth and Room Size
Seat depth — how far back the cushion extends from the front edge — affects both comfort and how much floor space the sofa needs. A deeper, more lounge-style seat gives a more relaxed, reclined sitting position, but takes up more room front-to-back than a shallower, more upright design. Neither is "correct" — it's a genuine trade-off between lounging comfort and floor space, worth weighing against how the sofa will actually be used and the depth of the room it's going into.
Measuring Your Room Before You Choose
A few simple measurements before you shop make the decision much easier: the length of wall or floor space available for the sofa, the depth available front-to-back (including room to walk past if needed), and the width of doorways or stairwells the sofa will need to pass through on delivery. For a modular sofa, it's worth sketching the configuration you're considering roughly to scale, since an L-shaped or curved layout needs space in two directions rather than one.
Circulation Space and Other Furniture
As a general rule of thumb, allow at least 90cm of walking space in front of a sofa where people will regularly walk past — more if it's a main thoroughfare through the room. It's also worth considering the sofa alongside the other seating in the room: a smaller, well-proportioned sofa paired with one or two armchairs can sometimes give a more comfortable, flexible seating arrangement than a single oversized sofa sized to fit everyone at once. Our armchair range is worth a look if you're considering this approach. As with other figures in this guide, treat this as a general starting point rather than a fixed requirement — the right amount of circulation space depends on the room and how it's used.
Everyday Use versus Entertaining
If the sofa is mainly for everyday family use, comfort, depth and a footprint that suits the room day to day usually matter more than maximum seating capacity. If you entertain more often, a modular design — such as the Pacific, Atlantis or Lapis ranges — offers the flexibility to reconfigure or add modules over time, without committing to a single large fixed layout from the outset.
Visit Our Richmond Showroom
Sofa comfort, depth and proportion are genuinely easier to judge in person. Our showroom at 477 Church Street, Richmond, has a range of fixed and modular sofas on display, including examples from Ditre Italia and Amura, and our team can help you work through sizing and configuration for your space. Browse the full sofa collection.