Blood Alcohol Concentration (BAC) Calculator

Bookmark this page and refresh it as your consumption progresses in order to monitor your estimated BAC in real time. Please Don't Drink And Drive!!!

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Your actual BAC is dependent on many complex factors, including your emotional and physical condition and health, and what you've recently ingested (including food, water, medications and other drugs). No blood/breath alcohol calculator is 100% accurate. The best that can be done is a rough estimation of your BAC level. You should not consider this to be a guideline for how much you can drink and still drive responsibly, or avoid being arrested! The best policy is don't drink and drive. Period.
The most commonly used BAC formula is referred to as the "Widmark formula". It can be summarized in the following formula:
[(# of drinks)(# oz. ethanol/drink)(0.0514 lbs. ethanol/oz.ethanol)(1.055 g ethanol/ml)]/[(weight of person in lbs.) * Widmark "r" value] * 100 - (B * time) where "r" refers to the percentage of body mass that contains alcohol (total body mass - mass of fat and bone), and B is the hourly decrease in BAC.
The US Department of Transportation uses a slightly different formula which is essentially an updated "Widmark formula":
[(# of drinks)(# oz. ethanol/drink)(23.36 grams ethanol/oz.)(0.806 ml H2O/ml blood)]/[(weight of person in lbs./2.2046 lb/kg)(TBW)(1000g/kg)] * 100 - (B * time) where TBW refers to the total body water volume and B is the hourly decrease in BAC.

* About History and Privacy

This app calculates your BAC on the server, but it doesn't store or log your history data on the server. That's not the way it works. This app saves your data back to you via http cookies, which we use to calculate your next update. We never store or log your history data on our end. This app is private--just between you and you.