How to Calculate the Exact Amount of Alcohol for a Wedding

If you are DIY-ing the bar at your wedding, holiday party, or backyard barbecue, you are likely terrified of two things: running out of alcohol while the party is still going strong, or over-buying and wasting hundreds of dollars.

Fortunately, professional caterers and event planners have standard mathematical formulas to ensure you buy the exact right amount of booze.

The Golden Rule of Party Drinks

The fundamental formula for any event is based on time and guest count: 2 drinks per guest for the first hour + 1 drink per guest for each additional hour.

For example, if you have 100 guests at a 5-hour wedding reception:

Hour 1: 100 guests × 2 drinks = 200 drinks
Hours 2-5: 100 guests × 1 drink × 4 hours = 400 drinks
Total: 600 drinks needed.

The 50/25/25 Split

Now that you know you need 600 drinks, what kind of drinks should they be? The standard open bar ratio is:

50% Beer: (300 beers)
25% Wine: (150 glasses of wine)
25% Liquor: (150 mixed drinks)

Converting to Bottles and Cases

You can't buy "150 glasses of wine" at the liquor store, so you have to convert those portions into retail packaging:

Beer: Sold in 24-pack cases. (300 beers ÷ 24 = 12.5 cases)
Wine: A standard 750ml bottle holds 5 glasses. (150 glasses ÷ 5 = 30 bottles)
Liquor: A standard 750ml bottle yields about 16 standard mixed drinks. (150 drinks ÷ 16 = 9.5 bottles)

Does this seem like too much math? Skip the calculator app and use our dedicated Party Drink Calculator. Simply plug in your guest count, party duration, and what you plan to serve, and it will instantly generate your complete shopping list!

Need exact calculations for your next kitchen project? Check out our free Party Drink Calculator to make the math effortless!