Blood Alcohol Concentration (BAC) Calculator
Estimate your blood alcohol concentration using the established Widmark model. Enter your body metrics, beverages consumed, and elapsed time to view a conservative estimation range, clinical impairment analysis, and metabolic clearance timelines.
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Please enter your weight and drink details to view your estimated BAC.
Understanding the Science Behind Your Estimate
The Widmark Pharmacokinetic Equation
First formulated by Swedish physician Erik Widmark in 1932, the equation models the relationship between the mass of alcohol ingested ($A$), body mass ($W$), volume of distribution ($r$), and steady hepatic elimination over time ($\beta \times t$). It remains the international standard for forensic ethanol estimation.
Why Food Delays Peak BAC
Food in the stomach closes the pyloric sphincter, trapping alcohol in the stomach where absorption is much slower than in the small intestine. While this can lower and delay peak BAC, it does not accelerate elimination once alcohol has reached the bloodstream.
Why 0.00% Is Not a Driving Clearance
When calculations project an estimated BAC of 0.00%, this represents a mathematical boundary rather than certified sobriety. Hangover symptoms, sleep deprivation, and post-intoxication cognitive fatigue continue to impair motor reflexes for hours after ethanol is cleared.