Calculate how much Alcohol you need for your wedding, event, or party with the fun and easy With A Twist Alcohol Calculator. Our awesome alcohol calculator will determine your needs!It determines how many bottles of wine, beer, and liquor you will need based on your specific guests. Our Wedding Bar Calculator is here to help you estimate the quantities of beer, wine, and mixer drinks you'll need to keep your guests happy. Suggested Consumption: A trusted Southwest Michigan bar service suggests an average consumption of 1.80 beers per person. Wondering how much alcohol you will need for your next event? Calculating Your Wedding Bar. Unsure how to budget and plan the bar for your wedding? Drink Calculator for your wedding, social, or corporate event know how much alcohol you will need to purchase for your event! A third beer choice is optional, but nice to offer.