Estimate blood alcohol concentration from intake and elapsed time.
Overview
Blood alcohol concentration (BAC) estimates how much alcohol is present in the bloodstream at a given time. It is commonly used for educational risk awareness and safer planning decisions.
BAC depends on alcohol consumed, body mass, distribution factors, and metabolism over time. Because individual metabolism varies widely, results should be treated as estimates rather than legal or medical certainty.
This calculator helps users understand how drink quantity and timing change intoxication risk. It is useful for harm reduction planning but should never justify driving or dangerous activity after drinking.
Steps
Provide body weight and sex-specific distribution setting.
Input number of drinks, volume, and alcohol percentage.
Specify hours since drinking began.
Tool applies Widmark-style estimate with metabolic reduction.
Use result as cautionary guidance, not legal proof of sobriety.
Math
BAC approximately (A x 5.14)/(W x r) - 0.015 x H
A is total alcohol in fluid ounces, W is body weight in pounds, r is alcohol distribution ratio, and H is elapsed hours. The metabolic term approximates average alcohol elimination over time.
Worked cases
Apply intake and elimination terms
Estimated BAC is elevated but below heavy-intoxication ranges for many users.
Higher A raises concentration despite elimination
Estimated BAC enters high-risk impairment range.
Subtract 0.015 x H term
Estimated BAC is significantly lower at 4 hours.
Why use this
Questions