Calculate how much Alcohol you need for your wedding, event, or party with the fun and easy With A Twist Alcohol Calculator. Calculate how much Alcohol you need for your Oklahoma 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. A good rule of thumb is to assume the average guest will consume two drinks during the first hour and then one drink for each hour thereafter. Read on for how to break that up for beer, wine and cocktails! Use this Wedding Alcohol Calculator to find out exactly how many drinks you should plan for your wedding guests. Wondering how much alcohol you will need for your next event? But they generally say 1 drink an hour per person, estimating about one third beer, one third wine, one third spirits. It always pays to estimate slightly high because running out is infinitely worse than having slightly too much.