BAC Calculator
Estimate your blood alcohol content (Widmark formula)
This is a rough estimate only. Never use it to decide whether to drive — if you've been drinking, don't drive.
Frequently Asked Questions
The Widmark formula: BAC = (alcohol grams ÷ (body weight in grams × distribution ratio)) × 100, minus alcohol metabolized over time (about 0.015% per hour). It's a widely used estimate, not a legal measurement.
Women generally have a higher proportion of body fat and lower body water content than men of the same weight, so alcohol is less diluted, producing a higher BAC from the same amount consumed.
In the US, a standard drink contains about 14 grams of pure alcohol — roughly a 12 oz beer (5% ABV), a 5 oz glass of wine (12% ABV), or a 1.5 oz shot of spirits (40% ABV).
The body metabolizes alcohol at roughly 0.015% BAC per hour, regardless of coffee, cold showers, or exercise — there is no way to safely speed this up.