Use this as a rule of thumb – these are averages for the number of bottles needed per hour per guest:

For every 25 guests, you will need 17 bottles of beer, 4 bottles of wine and 1 bottle of liquor (per hour).

For every 50 guests, you will need 34 bottles of beer, 7 bottles of wine and 2 bottle of liquor (per hour).

For every 100 guests, you will need 67 bottles of beer, 14 bottles of wine and 4 bottle of liquor (per hour).

* Keep in mind the above averages are PER HOUR, so multiply those by each hour your open bar will be available. Or you may limit each guest to two drinks per person. These are only suggestions (to give you an idea of how it typically works). Most guest get two bottles of each Alcohol bottle purchased if/when they do not intend to include Beer & Wine.