On average, how long will alcohol stay in your system?

Rule of thumb: This is a surprisingly complicated question, as it turns out, in terms of physiology. To make a long story short, the rule of thumb is that it takes about one hour for the average person to clear one "standard drink" (about 1/2 an ounce of ethanol). This equates to 12 ounces of beer (3.2%), 5 ounces of wine and 1.5 ounces of whiskey.

Short time: We metabolize about one drink per hour, faster in chronic drinkers, and slower in people with liver problems, which can be caused by alcohol. Most alcohol is metabolized in about 12-18 hours. Metabolites of alcohol can stay in blood and urine for much longer, up to 72 hours or more. The toxic effects of alcohol, however, can last indefinitely - the damage it does can be permanent.