Planning a wedding can be one of the most stressful periods of your life. If you don't hire a professional wedding planner, all of the details need to be handled by the bride, groom, or their families. There are two main options for a wedding bar. The first is a cash bar, where attendees pay for their own drinks. The second is an open bar, where drinks are provided at the cost of the hosts.

Step 1

Count the number of people on the guest list that may consume alcohol. Be sure to leave out any children under 21, and those who are pregnant.

Step 2

Calculate the total number of hours of the event.

Step 3

Multiply the number of drinking guests by the duration of the event. It is safe to assume that each person will have one drink per hour. Some guests will drink more, some less. Some guests that you figure will drink, won't drink at all. It all balances out to roughly one drink per person, per hour.

Step 4

Convert the number of drinks to bottles or cases. One bottle of wine is five glasses. One bottle of champagne is six glasses. Each bottle of beer is one drink. Each case of wine, champagne and beer normally has 12 bottles. A 5-gallon keg generally has 53 servings.

Step 5

Add up the total cost of the bottles, cases or kegs to find the total price of the alcohol.

Step 6

Multiply the bartender’s hourly rate by the event’s duration. Bartenders generally make $25 to $75 an hour. Add this value to the total value of the alcohol.

Step 7

Add in the cost of the glassware. This will vary based on where it is purchased. Your venue may provide glassware.

Bryan Clark has been a freelance writer since 2002. His work has appeared in "The New York Times," "USA Today" and the U.K.'s biggest paper—"The Guardian," amongst other, smaller publications.