Peak BAC Estimate Calculator

About this calculator

This calculator estimates peak blood alcohol concentration using the Widmark formula: BAC = (alcohol consumed in grams ÷ (body weight in grams × r)) × 100 − (β × hours elapsed), where r is the Widmark distribution factor (roughly 0.68 for men and 0.55 for women, reflecting differences in body water content) and β is the average metabolism rate of about 0.015% BAC per hour. Alcohol grams are derived from the number and type of drinks entered, and the metabolism term subtracts back out the amount your body has already processed since drinking started.

This tool is for education only, not legal or medical advice — actual BAC is affected by food intake, medications, liver function, and individual variation that the Widmark formula does not capture, and it should never be used to judge whether it's safe to drive. It's useful for understanding roughly how weight, sex, and drink pacing affect intoxication, a topic taught in health-education and responsible-drinking programs.