If you need to accommodate 40 people, you'll need 10 tables of four. If each table takes up around 6 × 6 feet of space, the total area for four persons is 36 square feet. So I have 360 square feet for 10 tables, but I also need room for service and my visitors' comfort, so I can quadruple that to roughly 750 square feet. Michael Young and Ross Boardman are correct. The basic math here is easy enough: 40 people x 6 feet per person = 240 square feet. But this calculation doesn't take edge cases into account, such as people who want to sit closer than six feet from others or groups who might like more space than one half of a table. It also doesn't factor in the size of the chairs or the amount of floor space available. In practice, this means that you need at least 750 square feet per 20 guests. If your room isn't that big, you're going to need to ask guests to share rooms or tables. You could also look into renting out additional spaces, such as an adjacent room or annex. And if you have a larger room than this, you should consider dividing it up even further. For example, you could create two 20-person areas with separate doors to prevent cross-contamination of food or drinks.