BAC Calculator
Estimate blood alcohol content based on drinks consumed, body weight, gender, and time elapsed.
lbs
hrs
Blood Alcohol Content
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Status —
Sober In (approx) —
How to Use This Calculator
Enter the number of standard drinks consumed, your weight, gender, and how many hours you have been drinking. The calculator estimates your current BAC, impairment level, and time until sober.
Formula
BAC = (Alcohol consumed in grams / (Body weight in grams × r)) × 100 - (0.015 × hours)
Where r = 0.68 for males, 0.55 for females. One standard drink = 14g alcohol. Metabolism rate = 0.015%/hour.
Where r = 0.68 for males, 0.55 for females. One standard drink = 14g alcohol. Metabolism rate = 0.015%/hour.
Example
Example: A 170 lb male, 3 drinks over 2 hours: BAC = (42 / (77110 × 0.68)) × 100 - 0.03 = 0.050% — some impairment, below legal limit.
Frequently Asked Questions
- In most US states, the legal limit for driving is 0.08%. Commercial drivers: 0.04%. Under 21: 0.00-0.02% (zero tolerance). Impairment begins well below 0.08%.
- One standard drink contains about 14 grams of alcohol: 12 oz beer (5%), 5 oz wine (12%), or 1.5 oz spirits (40%). Craft beers and cocktails often contain more.
- The body metabolizes alcohol at about 0.015% BAC per hour. There is no way to speed this up — coffee, food, and cold showers do not reduce BAC faster.
- Women typically have less body water and more body fat than men of the same weight. Since alcohol distributes in body water, women achieve higher BAC from the same amount of alcohol.