Below you will find the table that we at Hoecker Structures use to calculate the size of a marquee when
we only know the number of people and event type.
EVENT TYPE  Per Person
Concert style  6sq ft   0.56m2
Standing reception    8sq ft  0.74m2
Seated rows  9sq ft  0.84m2
Dining all seated  14sq ft  1.3m2
Dining & buffet  15sq ft  1.4m2
Dinner dance     16sq ft  1.5m2
Hospitality, reception, bar & dining    20sq ft  1.9m²