Finding A in the BAC Formula Calculator

To find A in the Widmark formula above, you multiply the number of liquid ounces of alcoholic beverages consumed by the percentage of alcohol in the beverage. For example, a typical bottle of regular beer contains 12 ounces of liquid and is 5% alcohol, so it contains .60 liquid ounces of alcohol.

BAC Formula Widmark

% BAC = (A * 5.14 / W * r) – .015 * H

A = liquid ounces of alcohol consumed
W = a person’s weight in pounds
r = a gender constant of alcohol distribution (.73 for men and .66 for women)
H = hours elapsed since drinking commenced (elapse duration is the time between alchol consumed and test taken)