Sofa dimensions: depth, seat height and the two-thirds rule

A sofa is bought for ten years and chosen in ten minutes — often without a tape measure in your pocket. Yet three measurements decide everything: seat depth, height, and the relationship to the wall that holds it.

Seat depth: the real choice of life

55-60 cm of seat to sit upright (entertaining, reading, conversation); 65-75 for the lounge where you half-recline. The sofas of the 1970s — the Togo first among them — also drop in height: 38-40 cm of seat instead of the standard 43-45. Superb, but anyone with fragile knees should try before buying.

Length: count in real seats

A real seat measures 60 cm between armrests: a "3-seater" of 180 cm offers only two comfortable ones. The true measurements: 2-seater 160-180 cm, 3-seater 210-240, corner sofa from 250 × 160. The two-thirds rule: the sofa should not exceed two-thirds of the wall that hosts it, otherwise it eats the room.

Around the sofa

35-45 cm between sofa and coffee table (close enough to set down a glass, far enough to pass your legs), 70-90 cm for walkways, and the coffee table at seat height ±5 cm. A rug under the whole arrangement: the front legs of the sofa on it, never straddling the void.

Material and colour, now that the measurements hold

Velvet for depth, beige for light, leather for patina. And for a general grounding in the genre, our 8 most famous design sofas — Togo, Camaleonda, Maralunga — explain where all today's shapes come from.

The mistakes that cost you a sofa

The first kills in the stairwell: measuring the living room but not the staircase, the lift and the diagonal of the front door — a non-removable-cover sofa of 240 cm will not "turn" in a narrow Haussmann building. The second settles: a foam density below 30 kg/m³ in the seat sags within three years, whatever the price. The third shows: very pale velvet with pets or children is a subscription to the dry cleaner's.

The Beyit advice

The fifteen-minute test: stay seated for a quarter of an hour in the shop, in your real evening position — discomfort never appears in the first thirty seconds. Insist on the seat density in writing (35 kg/m³ = very good), prefer the removable cover that doubles the lifespan, and with vintage, run your hand under the seat: webbing and suspensions can be redone for €150-300, a complete foam for €400-800. It is often the best deal on the market.

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