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The wall picks the sofa. The showroom only sells it.

What size sofa fits my wall? Enter the wall run and say what sits at each end — this sofa size calculator returns the width band that leaves honest clearance and names the standard sizes that land in it, from loveseat to sectional.

Wall run = the clear length of wall the sofa can live on, measured between whatever bounds it — corner to corner, or corner to the edge of a doorway. Sofa widths are overall, arms included.

    How a wall run becomes a sofa width

    01

    Three numbers, in this order

    • The wall run. Corner to corner, or corner to the near edge of a door casing. Not the room dimension on the plan — the actual clear wall.
    • What each end owes. An end table is 20–22″ wide and belongs 0–12″ from the arm; flush is correct, and that is a documented pairwise convention rather than a compromise. A walkway crossing the end of the sofa takes 30–36″. An open corner takes essentially nothing.
    • What is left is the sofa. Subtract, then look up which standard width lands under the answer. That last step is why so many living rooms end up with an 84″ sofa: it is what a 12-foot wall with two end tables leaves you.

    The calculator returns a band rather than a single number, because two of the three reserves have two honest values: a walkway is 36″ where the route matters and 30″ at its absolute floor, and a bare corner is a couple of inches or a comfortable half foot. An end table has only one — flush against the arm is the correct placement, not a compromise, so 22″ is 22″. Any standard size inside the band works. Above the band, something at the end of the wall has to give, and the tool names what.

    02

    Standard sofa widths

    Every number below is the same research-verified data Poché places on a floor plan, compiled from Architectural Graphic Standards, Time-Saver Standards and current US retail. Width × depth, in inches.

    PieceWidth × depthNotes
    Settee54 × 30entry, foot of bed
    Loveseat60 × 35 · 66 × 38two seats
    Apartment sofa72 × 35the small-space workhorse
    Standard sofa84 × 38the American default
    Grand sofa96 × 40needs a wall to match
    Sleeper sofa84 × 38closed; opens to ≈85–96″ deep
    Chaise sectional84 · 96 · 112 long62–68″ on the chaise leg
    L-sectional90 · 100 · 108 · 118measured along each wall
    U-sectional120 · 140returns face each other
    03

    Depth is the number people forget

    A wall run is a one-dimensional question and a living room is not. A grand sofa at 40″ deep, plus the 14–18″ it needs to reach the coffee table, commits about 56″ of the room before anything sits opposite it — in a 12-foot-deep room that is nearly half the floor gone. A deep-seat sofa in a showroom is a lovely thing; in a 12-foot room it eats a third more floor than it looks like it will.

    The other constraint that lives in the depth direction: a primary walkway wants 36″ and never goes under 30, and a secondary squeeze behind a chair can live at 24″. If the route from the door to the seats crosses in front of the sofa, that route is a primary walkway and it takes its 36 inches out of whatever the sofa left.

    04

    Seats, honestly

    Overall width sells the sofa; inside width seats the people. Capacity is 24″ of inside width per adult — arms excluded — and arms eat 13–17″ of the overall number. The binding body dimension is shoulder breadth rather than hip: ANSUR II puts 97.6% of adult males over 17.7″ across the deltoids, which is why 22–24″ is the real packing limit and 22 is a squeeze.

    SofaSeatsNotes
    Loveseat 48–60″1–248″ is one adult and a squeeze
    Sofa 72–84″2–3three only at the top of the band
    Grand 90–96″3four is a squeeze
    L-sectional 100–120″3–4count the corner separately

    The widely repeated "30 inches per person" is folklore, and applied to overall width it undercounts every sofa in the building. Full write-up: Sofa & sectional dimensions.

    !

    What this asserts, and what it does not

    The subtraction is pure geometry and we assert it. The end-table figure (20–22″ wide, 0–12″ from the seat) is a convention, traced through a peer-reviewed interior-layout paper to Panero & Repetto's Anatomy for Interior Designers — a real citation, and not a primary one, so we tier it as convention. The walkway figures come from the same clearance set Poché draws on a plan. The couple of inches at a bare corner is craft: nobody publishes it, and the calculator says so rather than manufacturing a standard. And whether the sofa gets into the room at all is a separate question with its own answer — will it fit through the door?

    Questions people actually ask

    What size sofa fits a 12-foot wall?

    A 12-foot wall is 144″. Put a 22″ end table at each end and you have 100″ of sofa to play with, which takes the standard 84″ sofa comfortably and the 96″ grand sofa with 24″ left at each end. If both ends are open corners, the wall itself is the only limit and a 96 still leaves two feet of breathing room. The number that usually decides it is not the wall at all — it is what has to pass in front of the sofa.

    How much space should be left at each end of a sofa?

    It depends what is there. An end table is 20–22″ wide and should sit 0–12″ from the arm — flush is correct, and that is a documented pairwise convention, not a compromise. If a walkway passes at the end of the sofa, reserve 30–36″: 36 is a primary route through the room and 30 is the absolute minimum. If the end is simply a corner, geometry allows the sofa to run right up to it, though a couple of inches keeps the arm from scuffing the return wall. That last one is craft, not a standard.

    How wide is a standard sofa?

    The American default is the 84-inch sofa, 84 wide × 38 deep. Around it: a settee is 54 × 30, a loveseat 60 × 35 or 66 × 38, an apartment sofa 72 × 35, and a grand sofa 96 × 40. Sectionals are measured as the length along each wall rather than as a bounding box, and run from 84″ for a small chaise sectional to 140 for a U-shape.

    Is a 96-inch sofa too big for a 12-foot room?

    On the wall, no — 96″ of sofa on a 144″ wall leaves 24″ at each end, which is an end table apiece. Across the room is where it bites. A grand sofa is 40″ deep, and it needs 14–18″ to the coffee table in front of it, so the sofa and its reach zone commit around 56″ of a 12-foot room before anything sits opposite. Depth is the dimension people forget.

    How many people does a sofa actually seat?

    Count inside width, not overall width: seating capacity is 24″ of inside width per adult, and arms eat 13–17″ of the overall measurement. So a 48″ loveseat is one adult and a squeeze, a 72–84″ sofa is two to three, and a 90–96″ grand sofa is three — four is a squeeze. The widely repeated 30 inches per person is folklore, and applied to overall width it undercounts every sofa on the floor.

    Should a sofa touch the wall?

    Against a wall is normal and costs nothing. A floated sofa wants 3–5″ behind it — enough to read as deliberate, not enough to lose a remote in — plus a real walkway behind that if anybody uses it as a route: 24–30″ for a secondary path, 36 for a primary one. Floating a sofa is how a big room gets a second seating group, and how a small room loses its walkway.

    Put the real sofa on the real wall.

    Upload the floor plan you already have, set the scale in seconds, and drop a true-scale 96-inch sofa onto the actual wall — clearance halos, walkways and all — then shop the size that proved out.

    Try it on your plan →