how many cocktails in half gallon?

There are approximately 20 cocktails in a half gallon. A standard cocktail recipe calls for 1.5 ounces of liquor. A half gallon is 128 ounces, so dividing 128 by 1.5 gives you approximately 85.3 cocktails. However, this number may vary depending on the exact cocktail recipe and the amount of ice and other ingredients used.