🍸 BAC Calculator (Blood Alcohol Content)
Estimate your approximate blood alcohol content (BAC) using the widely used Widmark formula.
How BAC is estimated
Blood alcohol content (BAC) is commonly estimated with the Widmark formula, which relates the amount of alcohol consumed to body weight and a distribution ratio that differs by sex, since body water percentage affects how alcohol is diluted in the body.
The formula
BAC (%) = (Alcohol consumed in grams ÷ (Body weight in grams × r)) × 100, where r is approximately 0.68 for men and 0.55 for women. The body then eliminates alcohol at roughly 0.015% BAC per hour, which this tool subtracts based on the time you enter.
- One standard drink is treated as about 14 grams of pure alcohol
- Elimination rate assumed: ~0.015% per hour
This is a rough mathematical estimate for general educational purposes only. Actual BAC varies with metabolism, food intake, medications and other factors. Never use this tool to decide whether it is safe to drive, and never drink and drive.