Sofa Size Calculator

About this calculator

This calculator recommends a sofa length by taking the wall width and subtracting clearance on each side — typically 6 to 12 inches (15–30 cm) per side, the space interior designers leave for walking room, end tables, or a floor lamp beside the sofa. Pushing a sofa edge-to-edge across a wall is a common furnishing mistake that leaves no breathing room in the layout and makes the piece look oversized relative to the room.

Interior designers and furniture shoppers use this before buying to avoid the two most common sizing errors: a sofa that overwhelms a wall with no clearance, or one so undersized it leaves an awkward gap, both of which are easy to spot in a showroom's open floor but hard to judge from a tape measure alone.