Measure the wall the sofa goes on. You get the sofa length that suits it, how each standard size looks there, and whether the sofa gets through your door.
Your sofa
A 72–84″ sofa for your 10′ walltwo-thirds of the wall is 80″: 72″ fits the rule, 84″ is a little over it for an extra seat · through a 36″ door on its back, 3″ to spare
Quick answer: a sofa looks right at about two-thirds of the wall it sits on, and as little as half when you want a side table and lamp at each end. A 10′ wall takes a 72–84″ sofa (two-thirds is 80″). The standard sofa is 72–96″ long and about 35″ deep; the most common three-seater is 84″.
How to use the sofa size calculator
- Measure the wall the sofa goes on, corner to corner, or the stretch between a door and a window where it will sit.
- Add a sofa you have in mind (optional) to see how much of the wall it takes.
- Check the door: the opening inside the frame with the door open, and the sofa’s depth, height and arm height from its listing, or its diagonal depth if the listing gives it.
- You get the sofa length that suits the wall, every standard size’s share of it, and whether the sofa goes through the door upright, on its back or tipped back, drawn to scale.
The rules behind the numbers
The wall. Homes & Gardens’ rule of thumb is “a sofa that’s about two-thirds of the wall length”. Sofas are sold in steps, “around 72, 84 or 96 inches”, so two-thirds often falls between two sizes, and then “there’s the option to go a little above two-thirds of the wall length with the larger sofa size in order to seat more”. Interior designer Bee Osborn goes smaller: “we tend to make the sofa half the size of the wall … to place side tables with lamps on either side”. This calculator gives the longest standard size inside two-thirds, the next size up, and every size’s share of your wall.
The sizes. Coleman Furniture puts a standard sofa at 72–96″ wide, 30–40″ deep and 30–36″ high, “the classic three-seater” at “84 to 90 inches wide, 35 to 38 inches deep”, a loveseat at 52–72″ and an L-shaped sectional at “95 to 130 inches on each side”. Chairish’s numbers agree: three-seat sofas 70–87″ long, “the most common length clocking in at 84″”, a standard depth of 35″ “but the range encompasses 32″ to 40″”, and a seat 21–22″ deep.
The door. A sofa goes through a doorway length first, so what has to fit the opening is its side: upright, its depth; on its back, its height; tipped back, its diagonal depth. Crate & Barrel: “for sofas and sectionals, the diagonal depth must be less than the width of the doorway in order to fit.” CB2 measures the diagonal depth with “a straight edge from the highest point of the back frame … to the front of the arm”, then “from the bottom rear corner of the sofa up to the point that bisects the straight edge”. Most sofa listings print it; the calculator never guesses it, because a sofa’s own shape decides it and a guess that comes out small says “it fits” when it does not.
Standard sofa sizes
| Sofa | Length | Depth | Height |
|---|---|---|---|
| Loveseat | 52–72″ | 30–36″ | 30–36″ |
| Standard sofa | 72–96″ | 30–40″ | 30–36″ |
| Three-seat sofa | 84–90″ (84″ the most common) | 35–38″ | 30–36″ |
| Sleeper sofa | 72–96″ | 36–40″ closed | 30–36″ |
| L-shaped sectional | 95–130″ each side | 36–40″ | 30–36″ |
Coleman Furniture’s ranges; the most common length from Chairish.
Sofa length by wall
| Wall | Two-thirds | Half | Sofa |
|---|---|---|---|
| 8′ | 64″ | 48″ | 60–72″ |
| 10′ | 80″ | 60″ | 72–84″ |
| 11′ | 88″ | 66″ | 84–96″ |
| 12′ | 96″ | 72″ | 96″ |
| 14′ | 112″ | 84″ | 96″, or a sectional |
Four worked examples
A 10′ living room wall. Two-thirds is 80″: a 72″ apartment sofa fits the rule and an 84″ three-seater is a little over it (70% of the wall) for the extra seat.
A 14′ wall. Two-thirds is 112″, longer than the 96″ sofas are sold in: a 96″ sofa, or an L-shaped sectional, 95–130″ a side.
7′ between a door and a window. Two-thirds is 56″: a loveseat of 52–56″.
An 84″ sofa, 37″ deep and 34″ high, to a bedroom door of 32″. Upright it needs 37″ and on its back 34″: neither fits. Its listing gives a 31″ diagonal depth, so it goes through tipped back with 1″ to spare. Through a 36″ front door it goes on its back, 2″ to spare.
Common mistakes
- Buying for the room, not the wall. The wall the sofa backs onto sets its length; a big room with a short wall still wants a shorter sofa.
- Forgetting the depth. A 40″ deep sofa sits 10″ further into the room than a 30″ one; the standard is about 35″.
- Measuring the door frame, not the opening. An open door takes some of the opening; measure inside the frame with the door open, or take the door off its hinges.
- Measuring the sofa with its cushions on. The diagonal depth is measured on the frame, “pillows not included” (Crate & Barrel).
- Measuring only the front door. Every hall, turn, stair and banister on the way in counts.
Next, size the coffee table for your sofa and the rug under it, or lay the whole room out in the free 2D planner.
Living room layout plannerRead next
- Sectionals for a small living room
- Large sectional sofa ideas
- Modular sofa ideas
- Console tables behind a sofa
Sofa size questions
What is the standard couch size?
A standard sofa is 72–96″ long, 30–40″ deep and 30–36″ high (Coleman Furniture); the most common three-seater is 84″ long and about 35″ deep (Chairish).
What size sofa for my living room?
About two-thirds of the wall it sits on, or half when you want a side table and lamp at each end: 72–84″ on a 10′ wall, 96″ on a 12′ wall.
What is the standard couch length?
72, 84 or 96″ are the usual steps; 84″ is the most common three-seat length.
What are loveseat dimensions?
52–72″ long, with the depth and height of a full sofa: 30–36″ deep and 30–36″ high.
What are sectional couch dimensions?
An L-shaped sectional usually runs 95–130″ on each side and 36–40″ deep; a U-shape 120–160″ or more (Coleman Furniture).
Will my couch fit through the door?
If its depth is less than the door’s opening it goes upright; if its height is, on its back; if not, compare its diagonal depth: Crate & Barrel’s rule is that “the diagonal depth must be less than the width of the doorway”.
How do you get a couch through a door?
Take the cushions off, open the door all the way (or take it off its hinges), and carry the sofa in length first: upright, on its back, or tipped back so its diagonal depth goes across the opening.