A sofa has three obvious dimensions and one hidden one that does all the work at a doorway. Width, depth, and height tell you whether it suits the room. The fourth number, the diagonal depth, is the straight line from the top back corner to the bottom front edge, and it is what a mover checks to decide whether the sofa can be tilted through an opening that looks too small. Measure all four, plus the seat height and whether the legs come off, and you can settle the question before the sofa is wedged in your hallway.
Stand the sofa upright as it normally sits. Place a straightedge (a yardstick or a taut string) from the highest point of the back frame down to the lowest point of the front of the sofa, usually the front of the seat rail or the bottom of the front arm. Measure that straight line. That diagonal is shorter than the height, so when you tilt the sofa to lead with a top corner, it presents the diagonal depth to the doorway instead of the full height. If the diagonal depth is less than the doorway clear height, the sofa can usually be walked through on an angle even when it is taller than the door is wide.
| Sofa type | Typical width | Typical depth | Typical height |
|---|---|---|---|
| Loveseat (2-seat) | 52 to 64 in | 32 to 40 in | 32 to 40 in |
| Standard 3-seat sofa | 78 to 88 in | 35 to 40 in | 33 to 40 in |
| Large / deep sofa | 88 to 96 in | 40 to 45 in | 36 to 42 in |
| Sleeper sofa | 72 to 91 in | 37 to 43 in | 35 to 40 in |
| Sectional (one section) | 60 to 100 in | 37 to 60 in | 33 to 40 in |
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Frequently asked
Measure four numbers: width (arm to arm), depth (front to back), height (floor to top of back), and the diagonal depth (top back corner to front bottom edge). The diagonal depth is the key one for a doorway, because the sofa usually goes through tilted. Compare it to the doorway clear height, and compare the sofa height or depth to the door clear width.
01It is the straight-line distance from the top of the sofa back down to the front bottom edge, measured with a straightedge across the side profile. Because it is shorter than the full height, tilting the sofa to lead with a top corner lets it pass a doorway using this diagonal rather than its height. Movers rely on it to judge tight openings.
02Measure the frame, without the loose seat and back cushions, for fit decisions. Cushions compress and can be removed during the move, so the rigid frame is the real limit at a doorway or on stairs. Measure with cushions only when you are checking how the sofa will look in the room.
03Taking the legs off usually drops the height by 3 to 6 inches and lowers the diagonal depth as well, which is often enough to clear a tight doorway or a low stair soffit. Most legs unscrew or unbolt in a few minutes, so it is the first thing to try before deciding a sofa will not fit.
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