Blood Alcohol Calculator (BAC)

Patient weight:
Percent of body capable of absorbing alcohol (Usual ranges): 
Male: 0.5 - 0.9   Average: 0.7
Female: 0.45 - 0.7   Average: 0.55  
Please double check the percent of absorption. Usual range: 0.45 - 0.75
Time spent drinking or time elapsed.  
Hours   (Enter zero for acute ingestion.)
Volume consumed:
Number of drinks:
See table below for common volumes and percentages.
Alcohol units: (e.g. 5% or 100 proof)


Blood alcohol concentration:

Blood alcohol level:
g/dL = %(w/v)

Specific Effects Related to the (BAC)

Disclaimer:  This is only a rough estimate based on population averages and does not take into account existing disease states, drug interactions, or age.

Background Info

Definition: Blood alcohol concentration (BAC) is the amount of alcohol in an individual's body, measured by the weight of the alcohol in a volume of blood.  The BAC limit determines the maximum amount of alcohol that can be consumed before it is illegal to operate a motor vehicle on a public road.

This program summarizes some of the effects that may be seen based on the calculated blood alcohol concentration. Generally, there is wide variation in alcohol tolerance among individuals and therefore the predominant effects may vary.   The effects of alcohol intoxication are greatly influenced by individual variations among users. Some users may become intoxicated at a much lower  blood alcohol concentration. Impairment can result from any level above 0.00.   Also, the degree of impairment rises dramatically as the BAC rises.

An individual's BAC depends upon that personís gender, weight, metabolism, time period over which the alcohol was consumed and the amount of food in the stomach prior to drinking. Although a person's BAC can be estimated, the level cannot be determined solely by the number of drinks consumed, and cannot be precisely calculated by a personís height and weight. 

In single-vehicle crashes, the relative risk of a driver with BAC between .08 and .10 is at least 11 times greater than for drivers with a BAC of zero, and 52 times greater for young males. Further, many studies have shown that even small amounts of alcohol can impair a person's ability to drive. 


All calculations must be confirmed before use. The authors make no claims of the accuracy of the information contained herein; and these suggested doses are not a substitute for clinical judgement. Neither GlobalRPh Inc. nor any other party involved in the preparation of this program shall be liable for any special, consequential, or exemplary damages resulting in whole or part from any user's use of or reliance upon this material.PLEASE READ THE DISCLAIMER CAREFULLY BEFORE ACCESSING OR USING THIS SITE. BY ACCESSING OR USING THIS SITE, YOU AGREE TO BE BOUND BY THE TERMS AND CONDITIONS SET FORTH IN THE DISCLAIMER.   Read the disclaimer
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