This method has been most recently described in: Curtin JJ, Fairchild BA. (2003). Alcohol and cognitive control: Implications for regulation of behavior during response conflict. Journal of Abnormal Psychology, 112, 424-436. PDF
The advantages of this method over the simpler Widmark equation are outlined here: Watson, P. E., Watson ID, Batt RD, Phil D (1981). Prediction of blood alcohol concentrations in human subjects. Journal of Studies on Alcohol, 42, 547-556 PDF
The alcohol dose required to produce a specific peak BAL is a function of the participant’s total body water (TBW), duration of the drinking period (DDP), time to peak BAL (TPB), and alcohol metabolism rate (MR). Specifically:
Alcohol dose (g) = ((10 * BAL * TBW)/0.8) + (10 * MR * (DDP + TPB)) * (TBW/0.8)
In the above formula, alcohol dose is measured in grams, BAL in g/100 ml (e.g., .010 g/100 ml) DDP and TPB in hours and TBW in liters. We use 0.015 g/100ml/h as the average metabolism rate for all participants. Additionally, we assumed that participants reached their peak BAL at 0.5 hours after cessation of drinking. TBW is determined from gender-specific regression equations provided in:
Watson, P. E. (1989). Total body water and blood alcohol levels: Updating the fundamentals. In K. Crow & R. Batt (Eds.) Human metabolism of alcohol (Vol. 1): Pharmacokinetics, medicolegal aspects, and general interest (pp. 41-58). Boca Raton, FL: CRC Press.
Men: TBW (l) = 2.447 – 0.09516* AGE (years) + 0.1074* HEIGHT(cm) + 0.3362* WEIGHT(kg)
Women: TBW (I) = -2.097 + 0.1069* HEIGHT(cm) + 0.2466* WEIGHT(kg)
Finally, alcohol dose is converted from grams to milliliters by dividing by the density of alcohol at 24° C, 0.7861 g/ml. Application of this procedure in several recent studies in our lab has resulted in both exceptional accuracy and minimal variability in observed peak BALs—especially relative to what is typically reported in alcohol challenge studies.
BAC Calculator Software
Calculates alcohol dose necessary to obtain target BAC based on height, weight, age, gender, and duration of drinking period: