What is BAC?
Blood alcohol content (BAC) refers to the percent of alcohol in a person’s bloodstream. A BAC of .10 percent means that an individual’s blood supply contains one part alcohol for every 1,000 parts blood. In Massachusetts, a person is legally intoxicated if he/she has a BAC of .08 percent or above.
Factors that determine BAC
- Number of standard drinks (see below)
- Amount of time in which drinks are consumed
- Body weight
- Food (to a much lesser extent)
One standard drink = 1/2 ounce of ethyl alcohol
- One 12 oz. regular beer (4.5 percent alcohol) = .54 oz.
- One 7 oz. malt liquor (7 percent alcohol) = .49 oz.
- One 4.5 oz. glass of wine (12 percent alcohol) = .54 oz.
- One shot (1.25 oz.) of 80-proof liquor (40 percent alcohol) = .50 oz.
More than one standard drink > 1/2 ounce
- One 16 oz. cup of beer = .72 oz. = 1.4 drinks
- One 40 oz. beer = 1.8 oz. = 3.6 drinks
- One 22 oz. malt liquor = 1.5 oz. = 3 drinks
- One 12 oz. glass of wine = 1.4 oz. = 2.9 drinks
- One 12 oz. margarita = 2-4 drinks, depending on ingredients
- One 12 oz. cup of trashcan punch = 4-10 drinks, depending on ingredients