• Under the American system, one "proof" is equal to one-half percent of alcohol by volume. This means a beverage that is 50% alcohol is 100 proof, a beverage that is 43% alcohol is 86 proof.
• In the United States, proof is a measure of the amount of absolute alcohol in distilled spirits or hard alcohol. It is calculated as the number of parts of alcohol in 200 parts of beverage at 60 degrees Fahrenheit.
• One standard drink or shot of hard alcohol is 1.25 ounces of 80 proof or 40% alcohol.

• Historically, the concept of proof came about before the 1700's when few people had equipment to make precise measurements of the percentage of alcohol in a beverage.
• To make sure the alcohol wasn't watered down; exotic formulas - such as igniting a mixture of equal parts of the beverage and gunpowder - were used to test the proof of distilled spirits.
• If the mixture of equal parts alcohol and gunpowder ignited, it was "proof" of a standard amount of alcohol content.

• Some mixed drinks have more than one standard shot in them (i.e. Long Island Ice Tea). Know what and how much you are drinking in one serving.
• Your level of intoxication and type of experience will be different if you are drinking hard alcohol that is 80 proof or 40% alcohol versus hard alcohol that is 150 proof or 75% alcohol.
• You can moderate your use of alcohol and avoid negative consequences by not drinking past the point when you just begin to feel a mild buzz from the alcohol or not drinking at all. For example, this would be about 0 - 3 drinks in 3 hours for a 130 pound female, or 0 - 5 drinks in 3 hours for a 180-pound male.

Party Safe, Party Smart !

Reference:Dimeff, L., Baer, J., Kivlahan, D., Marlatt, A., (1999).Brief Alcohol Screening and Intervention for College Students(BASICS):A Harm Reduction Approach. NY, NY: The Guilford Press.