How the BAC calculator works
BAC is estimated with the Widmark equation using the number of standard drinks, the selected body weight, the sex-based distribution ratio, and the time since the first drink. The result is reduced by a fixed elimination rate of 0.016 per hour.
Formula: BAC = ((Dose in grams / (Body weight in grams × r)) × 100) - (0.016 × hours)
Standard drink reference
- Beer: 12 oz / ~5% ABV
- Wine: 5 oz / ~12% ABV
- Liquor: 1.5 oz / ~40% ABV
What changes the result
- Higher body weight generally lowers BAC.
- More drinks increase the dose in grams.
- More time decreases the estimate via metabolism.
Safety and interpretation
BAC estimates can differ substantially from real-world impairment. Food intake, medication, drinking speed, sleep, and individual metabolism all affect how alcohol is absorbed and processed. Do not use this page to determine fitness to drive or operate machinery.