Allow 12-15 sq ft per guest for round tables, plus 2-3 sq ft per guest for the dance floor, then add 20-25% for perimeter poles, staking, sidewalls and uneven ground. That is why 100 guests with a dance floor land on a 40x60 ft tent (2,400 sq ft). Our guide on
how to calculate wedding venue capacity explains the full formula for indoor and outdoor spaces.