Modified Widmark Calculator
Using Watson Total Body Water,
Alcohol correction for density,
and updated beta calculations
programmed by Stephen Z. Fadem, M.D., FASN


Beer ~ 12 oz. ~ 4-4.5%
Wine Glass ~ 4 oz. ~ 15-20%
1 Shot ~ 1.5 oz ~ 30-50%

Fluid Ounces Consumed

Percent Alcohol
Your Weight (Lbs)
Your Height - feetInches -
Your age (yrs)
Hours Consuming Drink
BAC Percentage: ____
BAC Analysis: ____
Blood Alcohol Level percent = (v X z X d)/(r X M) - β *t
v = volume
z = percent per volume
d = density of alcohol (0.789 g/mL)
M= weight converted to kg
R = Rho - .73 for men and .66 for women (from Widmark)
β=beta= elimination rate 0.17*BAC
t= time - Hours since drinking started
Maskell, PD, Korb, A-S. Revised equations allowing the estimation of the uncertainty associated with the Total Body Water version of the Widmark equation. J Forensic Sci. 2021; 00: 1– 5. https://doi.org/10.1111/1556-4029.14859