SSS BAC Calculator

USA TODAY opinion piece, U.S. Traffic Safety Misleads the Public: As GM ignition case shows, technology is emphasized over driver behavior, Sept.2014

AJPH Editorial 20,000  more Americans killed annually because US traffic-safety policy rejects science. Aug. 2014

New paperback copies of classic 1991 Traffic Safety and the Driver available on ($29.95), Kindle ($9.99)

Information on 2004 book  

How to Purchase Traffic Safety

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Free Blood Alcohol Concentration (BAC) calculator


Estimate* your blood alcohol level, or Blood Alcohol Concentration (BAC) after consuming a number of drinks
(BAC is the percent, by weight, of alcohol in the blood)  
Driving with a BAC of 0.08% or greater is illegal in all US states (lower levels apply in most other countries)


What is your sex?
How many drinks did you have?
How much time did you spend drinking?
What do you weigh?


The background to this calculator and the formulas used to calculate BAC are from
Chapter 10, Alcohol and Traffic Safety
of Traffic Safety

How to purchase Traffic Safety         Table of Contents


*The estimates are based on drinks containing 0.5 fluidounces (15 mL) of alcohol, close to a typical serving of beer, wine, or spirits. The same amount of alcohol consumed in the same time produces approximately the same BAC, regardless of the type of drink. About 0.5 fluidounces of alcohol is contained in a typical serving of beer (12 fluidounces), of wine (4 fluidounces,) or scotch (1.3 fluidounces -- although a common measure is 1.5 fluidounces) or other similar strength liquor.

These are typical estimates. The BAC reached by an individual may vary for many reasons, including food consumption. The performance and behavior changes at a given BAC vary substantially between individuals. This calculation is a guide based on average responses. There is no guarantee that you will be measured to be within legal limits even if the calculation indicates that you are marginally legal.

Blood Alcohol Concentration (BAC) is the percent, by weight, of alcohol in the blood. It is illegal to drive with a BAC exceeding an amount specified in law. Legal limits vary - from 0.02% in Sweden to 0.08% in all US states (as of November 2005).


Revised 2014-12-18