You probably already know that operating a vehicle with a blood alcohol concentration (BAC) of .08% or higher is illegal. However, the effects of alcohol can be felt much earlier, oftentimes being present from the first or second drink. Understanding how much it takes for these effects to become evident can help you avoid drunk driving behavior. 

What is a standard drink size? 

BAC is calculated by how many standard drinks you have during the night and the potency of the alcohol determines the standard drink size associated with it. Beer has 5% alcohol content, which is relatively low compared to liquor, which is 40% alcohol content or higher depending on what you are drinking. Accordingly, a standard size beer is 12-ounces, while a standard size glass of liquor is 1.5-ounces (commonly referred to as a shot). Because wine has 12% alcohol content, its standard size is 5-ounces. Along with potency and drink size, your height, weight, and gender can also impact your tolerance. 

How many drinks does it take to get drunk? 

In general, the following BAC measurements are associated with these effects: 

  • .02% – .05% (2 to 3 drinks): Visual function and multi-tasking ability are both in decline at this point. Coordination is also impacted, which can affect steering ability. If an unexpected driving situation occurs, the driver is less likely to respond to it in an effective manner.  
  • .08% – .10% (4 to 5 drinks): You may experience problems with short-term memory. You may also have difficulty regulating your speed. Coordination declines further, as does thinking and speech. You may drift in and out of your line or drift onto the shoulder of the road.  
  • .15% (7 drinks): Muscle control is degraded, and information processing will also be affected. You may be unable to pay adequate attention to the task at hand, which increases the odds of experiencing an accident.