ABSTRACT
Maximum blood alcohol levels after a drinking event can be calculated by using Widmark’s Formula,
named in honor of the pioneering studies by Erik M.P. Widmark of Sweden.
For men with normal body weight (i.e., body length in centimeters minus 100 should correspond to weight in kg), the formula is:
An example: After downing half a liter of beer (20 g alcohol), the blood alcohol level of a man weighing 88 kg should not exceed 0.32 ‰ (or 340 mg%); that is, 20/(88
∗
0.7) = 20/62 = 0.32. Widmark’s rho factor of 0.7 is a dimensionless constant that was empirically arrived at by
relating administered alcohol dose, body weight, and measured blood alcohol level (all given in mass units). Widmark’s rho factor (sometimes given as Widmark’s “r” factor) corresponds to the volume of distribution (V
, unit: l kg
, i.e., volume/mass) for alcohol in the following way: rho = 1.055
∗
V
(1 ml whole blood weighs 1.055 g).
