Blood alcohol content (or blood alcohol concentration), often abbreviated BAC, is the concentration of alcohol in blood, measured, by volume, as a percentage. For example, a BAC of 0.20% means 1 part per 500 in an individual's blood is alcohol.

How much is too much?
Use this blood alcohol content calculator to estimate just how little alcohol it takes to put you on the "wrong side of the law".

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NOTICE: This blood alcohol content calculator is only a reference and not absolutely accureate to be considered legal evidence. The figures you calculate are averages. Individuals may have varying results depending on their personal metabolism of alcohol. Food in your stomach may affect the rate of absorption. Factors such as medications, health and psychological conditions may also change your degree of impairment. Smart Start discourages anyone who has been drinking from driving, even if they are within legal limits.

Smart Start services ignition interlock systems in the following states:

Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Georgia, Illinois, Indiana, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Missouri, New Hampshire, New Jersey, New Mexico, New York, Ohio, Oklahoma, Oregon, Pennsylvania, Tennessee, Texas, Utah, Washington, and Wyoming.