The evening
Look for
3,400 – 3,778 sq ft
A range, because the inputs underneath it are bands rather than constants. Quoting a single figure would put a precision on this that the arithmetic does not have.
The bottom of that range is not a rule of thumb. It is 3,400 sq ft because that is the smallest floor the plan solver could actually draw this evening in — a room with nothing spare, and one to walk out of rather than negotiate over. The top of the range is the same room at this format’s generous end.
Where it goes
Rounds
120 guests × 13.5 sq ft, the planning factor for rounds.
1,620 sq ft
Dance floor
40% of 120 on the floor at once at 3 sq ft each — about 12 × 12 ft.
144 sq ft
Bar
8 × 3 ft each, plus the 6 ft queuing apron in front that nobody seats into.
72 sq ft
Circulation and service
Whatever is left once the programme is placed — the 4 ft service aisle at the wall, the walkways between tables, and the floor a seating grid cannot use because it does not divide.
1,564 sq ft
When you are standing in it
- A room of roughly 3,400–3,778 sq ft of USABLE floor — not the figure on the brochure, which is usually the whole room including the columns.
- Ask what the ceiling is. Rounds wants at least 10 ft.
- Somewhere to put service that is not in the middle of the guest route. A bar on the main walkway makes a queue and a bottleneck out of the same six feet.
- A clear span for the dance floor. A column in the middle of it is the one obstruction that cannot be planned around.
What this assumes
- A planning envelope, not a legal occupancy limit. What a room may hold is set by the local fire authority.
- The figure assumes a room roughly half as deep as it is wide. The same floor area long and thin seats fewer — 3,718 sq ft at 26 ft wide is a corridor, not a ballroom.
- Figures come from the same allowances the floor-plan drawing uses, so a room that meets this should draw a plan that works.