What is “blood alcohol content” (BAC) or level?

Blood alcohol content (BAC) is a metric of alcohol in your blood stream at the time you are stopped for a DUI. All states have a minimum BAC of .08% for adults, so if you’re BAC is at or above that level, you’ll be charged with DUI. Also, most states have “zero-tolerance” DUI laws for drivers under 21 years old. In these states, the BAC for drivers under 21 could be as low as .01%.