There are formulas that one can use to calculate an estimated spend per person but they vary based upon the event, the individual who is attending the event and the price of the food and/or beverage.That said, an individual who is attending a cash bar reception at a hotel may consume two beverages of his choice at a price point that will range from $6 for a beer to $10 for a mixed drink.You will need to calculate the average price point, in this case it is $8 at 2 drinks...$16.00 per person.