How Many Seats Fit a Room
Add each piece's width together, plus a gap of a few inches between pieces for someone to walk past, and compare the total against the wall run available. That total, not the seat count, is what decides whether a combination fits.
The formula
For any combination of pieces standing side by side along one wall: sum each piece's published width, then add a walking gap between pieces - six inches is a workable minimum, more if the gap doubles as a walkway rather than just a visual break. That total is the wall run the combination needs, and it is always larger than the sum of the widths alone.
A worked example
Both pieces' widths are pending measurement here - once fit is filled in, this example computes automatically rather than needing to be rewritten.
Why this is not the same question as one piece's own sizing page
Each piece's own sizing page answers whether that single item fits a doorway, a wall and a room depth on its own. This guide is the arithmetic for when more than one piece is going against the same wall - a three-piece set, or a chair bought to sit beside an existing sofa. The per-item figures do not change; they are simply added together with a gap between them.
Depth still applies to every piece in the row
Combining seats along a wall does not reduce how far any one of them needs to recline into the room. If three reclining seats share a wall, the room still needs the deepest one's reclined depth clear in front of the whole row, not just in front of the middle seat. See the sizing pages for each piece's own reclined-depth figure.
Questions
How much gap should I leave between two recliners?
Six inches is a workable minimum for a visual break; allow more if that gap also needs to work as a walkway.
Does combining seats change how far each one reclines into the room?
No. Each piece still needs its own reclined depth clear in front of it - combining seats along a wall is a separate question from how far any one of them extends forward.
Is a 3-piece set's total wall run published anywhere?
Where a set is sold as one listing, its stated width is normally for the whole set already - check the specific listing rather than adding piece widths that may already be summed.
What if I am adding one chair to an existing sofa?
Add the chair's width to the sofa's, plus a gap between them, and compare that total to the actual wall - the same formula as combining any two pieces.