Blood alcohol content (BAC), also called blood alcohol concentration or blood alcohol level, is a measurement of alcohol intoxication used for legal or medical purposes. For example, a BAC of 0.10 (0.10% or one tenth of one percent) means that there is 0.10 g of alcohol for every 100 ml of blood, which is the same as 21.7 mmol/l. A BAC of 0.0 is sober, while in the United States 0.08 is legally intoxicated, and above that is very impaired. BAC levels above 0.40 are potentially fatal.
