Enter your gender, body weight, and time since drinking, then add the number of drinks (beer, wine, or spirits) you've consumed. The BAC Calculator estimates your Blood Alcohol Content (%), tells you your impairment status, and shows how long until your BAC returns to zero.
Estimated BAC
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Impairment Status
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US Legal Driving Status
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Hours Until BAC = 0.00%
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Hours Until BAC < 0.08%
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Total Standard Drinks
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BAC is estimated using the Widmark formula, which considers the total grams of alcohol consumed, your body weight, a gender-based distribution ratio (0.68 for males, 0.55 for females), and the alcohol metabolized over time. The standard metabolism rate is approximately 0.015% BAC per hour. This calculator provides an estimate — actual BAC can vary based on metabolism, food intake, medications, and other individual factors.
In the United States, the legal BAC limit for drivers aged 21 and over is 0.08%. For drivers under 21, zero-tolerance laws apply in most states, with limits ranging from 0.01% to 0.05%. Commercial drivers are held to a stricter limit of 0.04%. Exceeding these limits can result in DUI or DWI charges.
In the US, one standard drink contains approximately 14 grams (0.6 oz) of pure alcohol. This is equivalent to a 12 oz regular beer at 5% ABV, a 5 oz glass of wine at 12% ABV, or 1.5 oz of distilled spirits at 40% ABV. Knowing standard drink sizes helps you track consumption accurately.
Gender affects BAC because males and females have different body water percentages. The Widmark distribution ratio is 0.68 for males and 0.55 for females, meaning alcohol is more concentrated in women's blood for the same amount consumed. Women also tend to have less of the enzyme alcohol dehydrogenase, which breaks down alcohol in the stomach.
On average, the body metabolizes alcohol at a rate of about 0.015% BAC per hour. So if your BAC is 0.09%, it would take roughly 6 hours to reach 0.00%. This rate can vary slightly depending on individual factors like liver function, body composition, and whether food was consumed.
No — coffee, cold showers, food, and exercise do not significantly speed up alcohol metabolism. The liver processes alcohol at a fairly fixed rate of roughly one standard drink per hour. Time is the only reliable way to lower your BAC. This is why it's important to plan ahead if you intend to drive.
Even at low levels (0.02–0.05%), alcohol can impair judgment, coordination, and reaction time. At 0.08% (the US legal limit), significant impairment in motor control and reasoning occurs. At 0.15% and above, severe impairment, loss of balance, and vomiting are common. Levels above 0.30% can be life-threatening.
This calculator provides an estimate based on the widely used Widmark formula and is intended for educational purposes only. It should not be used to make decisions about driving or any activity where impairment poses a risk. Individual BAC can vary due to factors like hydration, food consumption, medication use, and genetics.