qBAC, quick Blood Alcohol Content/Concentration estimator.
qBAC provides a quick and easy way to run "what if" scenarios regarding alcohol consumption, and includes a comprehensive drink database and the ability to modify many variables involved in BAC calculations.
qBAC should NOT be used to determine if you can drive safely after consuming alcohol. Never drink and drive. It is a "what if" and educational tool only. It intentionally does not include anything to gauge ones level of intoxication relative to any laws or regional standards. Again, it is not a drink counter, it is a "what if" utility.
For additional information regarding BAC, Wikipedia has great
cited references, in addition to its information.
http://en.wikipedia.org/wiki/Blood_alcohol_content