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Blood Alcohol Content Calculator

Notice: Please note that if you have been charged with a drunk driving offense, you will benefit from consulting a criminal defense lawyer. For information about what you should do after an arrest for drunk driving, please see this associated article. If you wish to hire a defense lawyer, you may find this article on "How To Hire A Lawyer" to be helpful.

The following calculator will let you estimate your blood alcohol content (BAC), based upon the number of drinks you have consumed over a specified period of time.

For the sake of simplicity, the calculator works on the assumption that you have consumed the same types of drinks - if you have consumed different types of drinks, you may wish to run the calculator based upon the stronger drinks you have consumed. You should round up (not down) to the nearest drink.

Please note that the calculator assumes that your consumption has been consistent over the period specified (e.g., if you have consumed three drinks in three hours, the calculator assumes that you have consumed one drink per hour, not one drink three hours ago and two more within the last fifteen minutes.) Also, the calculator assumes that your drinks are of a typical strength. If you are consuming drinks that are stronger than is typical, the calculator will underestimate your BAC.

While the calculator can provide a good estimate of your blood alcohol content, please do not rely upon the resulting figure to determine if it is "safe" or "legal" to drink and drive. If you have consumed enough alcohol to be concerned about driving, whatever your blood acohol content may be, you should find alternate transportation.

The analysis assumes a legal limit of 8mg of alcohol per 100 mL of blood (0.08). If your jurisdiction applies a different legal limit, you should compare your BAC percentage to that limit. This calculator cannot substitute for an actual breath or blood test for alcohol. No matter what your jurisdiction, you should treat the BAC estimate as a very rough approximation and should not rely upon the analysis comment.

Blood Alcohol Content (BAC) Calculator

Number of Drinks Consumed
Type of Drinks Consumed

Your Weight (lbs)
Hours Consuming Drink(s)
BAC Percentage
BAC Analysis

Remember - when in doubt, don't drive. Please recall also that if your driving skills are impaired as a result of the consumption of alcohol, some jurisdictions will prosecute you for drunk driving even if your blood alcohol content is below the "legal limit".