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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  
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. 50% or 100 proof)
Disclaimer:  This is only a rough estimate based on population averages and does not take into account existing disease states, drug interactions, or age.

Typical Volumes and Concentration

Beverage Usual Volume Usual Concentration
Beer 12 or 16 oz 5.0 %
Wine 2.5 or 5oz  12.0 %
1 Shot 1.25 oz 80 proof

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 person’s 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 person’s 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. 

ABW versus ABV??


The concentration of alcohol in a beverage is usually stated as the percentage of alcohol by volume (ABV) or as proof.  Some tables may list the alcohol concentration as ABW (alcohol by weight).

To convert ABW to ABV, you must divide the ABW by the specific gravity
of alcohol which is ~0.787

Therefore 4.3% ABW/ 0.787 = 5.46% ABV.  Alternatively you can multiply the ABW (alcohol by weight) by 1.271.

Summary:   ABV = ABW / 0.787  or   ABV = ABW x 1.271

Alcohol Content

Alcohol Content (in Percent) of Selected Beverages
Beverage Alcohol Content (%) Usual Serving size
Beers (lager) 3.2 - 4.0 1 can/bottle = 355 ml = 12 fl. oz.
Ales 4.5 1 can/bottle = 355 ml = 12 fl.oz.
Porter 6.0 1 can/bottle = 355 ml = 12 fl.oz.
Stout 6.0 - 8.0 1 can/bottle = 355 ml = 12 fl.oz.
Malt Liquor 3.2 - 7.0 1 can/bottle = 355 ml = 12 fl.oz.
Sake 14.0 - 16.0 one shot = 44 ml = 1.5 fl. oz. (Range: 1.25 to 1.5 fl.oz. or 37 - 44 ml)
Table wines 7.1 - 14.0 one glass = 148 ml = 5 fl. oz.
Sparkling wines / Champagne  8.0 - 14.0 one glass = 148 ml = 5 fl. oz.
Fortified wines 14.0 - 24.0 one glass = 148 ml = 5 fl. oz.
Aromatized wines 15.5 - 20.0 one glass = 148 ml = 5 fl. oz.
Brandies 40.0 - 43.0 one glass = 148 ml = 5 fl. oz.
Whiskies 40.0 - 75.0 one shot = 44 ml = 1.5 fl. oz. (Range: 1.25 to 1.5 fl.oz. or 37 - 44 ml)
Vodkas 40.0 - 50.0 one shot = 44 ml = 1.5 fl. oz. (Range: 1.25 to 1.5 fl.oz. or 37 - 44 ml)
Gin 40.0 - 48.5 one shot = 44 ml = 1.5 fl. oz. (Range: 1.25 to 1.5 fl.oz. or 37 - 44 ml)
Rum 40.0 - 95.0 one shot = 44 ml = 1.5 fl. oz. (Range: 1.25 to 1.5 fl.oz. or 37 - 44 ml)
Tequila 45.0 - 50.5 one shot = 44 ml = 1.5 fl. oz. (Range: 1.25 to 1.5 fl.oz. or 37 - 44 ml)


Alcohol Content of Some Typical Drinks
Mixed drinks are based on typical drink recipes using 80 proof liquor. The amount of alcohol in actual mixed drinks may vary.
Drink Alcohol Content
Manhattan 1.15 oz. (34 ml)
Dry Martini 1.00 oz. (30 ml)
Malt liquor -12 oz. (355 ml) 0.71 oz. (21 ml)
Airline miniature 0.70 oz. (21 ml)
Whiskey Sour/Highball 0.60 oz. (18 ml)
Table Wine - 5 oz. (148 ml) 0.55 oz. (16 ml)
Beer - 12 oz. (355 ml) 0.54 oz. (16 ml)
Reduced Alcohol Beer 0.28 oz. (8 ml)

Don't forget to check out the extensive health section....

Disclaimer

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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