Widmark Bac
Calculator

It calculates estimated BAC using the amount of alcohol consumed, body weight, a sex-specific distribution constant (reflecting typical differences in body water percentage), and time elapsed since drinking began, accounting for the body's steady rate of alcohol metabolism. It was originally developed for forensic and research purposes.

Women generally have a higher average percentage of body fat and lower percentage of body water than men at the same weight, and alcohol distributes primarily into body water, meaning the same amount of alcohol typically produces a higher BAC in women than in men of equal weight. The distribution constant (commonly around 0.68 for men and 0.55 for women) reflects this average physiological difference.

The Widmark formula relies on population averages and doesn't account for individual variation in metabolism, food consumption, medication use, drinking pace, or genetic differences in alcohol processing, all of which can meaningfully shift actual BAC from the estimate. It should never be used to judge whether it's safe to drive or to contest a legal BAC reading.

Yes, food in the stomach slows alcohol absorption significantly, which the basic Widmark formula doesn't account for, so actual peak BAC after eating is often lower and delayed compared to what the formula predicts for the same amount of alcohol on an empty stomach. This is one of the formula's most significant real-world limitations.

It's mainly useful for general education about how factors like weight, sex, and time affect alcohol processing, or for rough, non-critical estimation in research and harm-reduction contexts. Any decision involving safety, legality, or health should never rely on this estimate alone.