BAC Calculator
Estimate blood alcohol content from drinks consumed, body weight, gender, and time elapsed.
Formula: Widmark formula: BAC = (alcohol grams ÷ (body weight in grams × r)) × 100 − 0.015 × hours, where r = 0.68 (men) or 0.55 (women).
A rough estimate, not a substitute for a breathalyzer — actual BAC is affected by food, medication, liver function, and other factors. The US legal driving limit is 0.08%.
Worth Knowing
This applies the Widmark formula to estimate blood alcohol content from drinks, body weight, sex, and time, but the result is a rough approximation and must never be used to decide whether it's safe to drive. Real BAC varies with food in the stomach, medications, liver function, and individual metabolism, none of which a formula captures. The body clears alcohol at a fixed rate of roughly 0.015% per hour that nothing — coffee, cold showers, or water — can speed up.
How to Use
- Enter Gender into the first field of the BAC Calculator.
- Fill in the rest: Body weight, Standard drinks consumed, Hours since you started drinking.
- Your result appears instantly as you type — there's no submit button or page reload.
- A rough estimate, not a substitute for a breathalyzer — actual BAC is affected by food, medication, liver function, and other factors. The US legal driving limit is 0.08%.
Formula
Widmark formula: BAC = (alcohol grams ÷ (body weight in grams × r)) × 100 − 0.015 × hours, where r = 0.68 (men) or 0.55 (women).