Studio Matrx Monthly · Volume 1 · Issue 2 · July 2026
Amogh N P
 In loving memory of Amogh N P — Architect · Designer · Visionary 
← The Furniture Hub

Sofa Size Calculator

Find the sofa length that suits your room. Enter the wall the sofa will sit against and this uses the designer's two-thirds rule to give a recommended length, the seats it holds and the breathing space to leave each side.

12 ft

The clear wall the sofa faces or backs onto — not the whole room.

60 cm

A comfortable seat is ~55-65 cm wide. Deep-lounge seats are wider.

15 cm

Slim arms ~10-15 cm; chunky arms 25-30 cm. Armless sofas seat more in the same length.

Recommended sofa length
0.0 ft

~244 cm — two-thirds of a 12 ft wall.

3
Seats it holds
61 cm
Space each side

Leave about 40 cm between the sofa and the coffee table, and keep a 60-90 cm walkway around it. A sofa that runs the full wall makes a room feel boxed in.

Indicative only. The two-thirds rule is a starting point, not a law — a floating sofa, an L-shape or a large room changes it. Before you buy, tape out the footprint on your floor and check the delivery path: door, lift and staircase widths defeat more sofas than living rooms do. See the sofa buying & sizing guide.