Blood-alcohol calculations are often required in forensic science casework, they commonly used the Widmark equation. Anthropometric equations can tailor Widmark's rho-factor for a given individual. Results using anthropometric equations were in reasonably good agreement with rho-factors determined empirically. A regression equation involving the person's age, height and body weight was the best model for male subjects. Consideration of the person's BMI gave more accurate results for females.