Our professional-grade BAC calculator gives you precise estimates of your blood alcohol concentration based on your drinks, weight, gender, and time. Make informed decisions about your alcohol consumption and know when it's safe to drive.
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Blood Alcohol Content (BAC) is a critical measurement that determines how alcohol affects your body and behavior. Our professional-grade BAC calculator offers precise estimates to help you make informed decisions about alcohol consumption and personal safety.
Blood Alcohol Content (BAC) represents the percentage of alcohol in your bloodstream. It's measured as grams of alcohol per 100 milliliters of blood. For example, a BAC of 0.08% means 0.08 grams of alcohol per 100ml of blood—the legal driving limit in most U.S. states.
BAC is the most accurate way to measure intoxication levels and is used by law enforcement worldwide to enforce drunk driving laws.
Different BAC levels produce distinct effects on your body and behavior:
Many factors influence how quickly your BAC rises and falls:
Our BAC calculator uses the Widmark formula, the gold standard for BAC estimation. The formula accounts for:
The formula calculates BAC = (Alcohol consumed in grams / (Body weight in grams × r)) × 100, where r is the gender-specific distribution factor.
DUI (Driving Under the Influence) limits vary globally:
Commercial drivers and individuals under 21 typically face stricter limits in most jurisdictions.
Follow these guidelines to drink responsibly:
Remember: The safest BAC for driving is always 0.00%.
A "standard drink" contains approximately 14 grams of pure alcohol, roughly equivalent to:
Craft beers, high-proof spirits, and large serving sizes can contain multiple standard drinks, often leading to underestimation of alcohol consumption.
Beyond impaired driving, high BAC levels pose serious health risks:
Regular heavy drinking can lead to tolerance, meaning higher BAC levels are needed to feel effects, increasing long-term health risks.
BAC can be measured through several methods:
While our calculator provides accurate estimates, these are the only definitive ways to measure actual BAC.
Get answers to common questions about blood alcohol content and our calculator
BAC calculators provide estimates based on scientific formulas like the Widmark equation. Our calculator is highly accurate when all information is entered correctly. However, individual factors like metabolism rate, recent food consumption, medications, and overall health can affect actual BAC levels. For legal purposes, only breathalyzer or blood tests administered by law enforcement or medical professionals should be considered definitive.
Gender influences BAC for several physiological reasons. Women typically have higher body fat percentages and lower water content than men of the same weight. Since alcohol is water-soluble but not fat-soluble, this results in higher concentration in the bloodstream. Additionally, women generally have lower levels of the enzyme alcohol dehydrogenase (ADH), which breaks down alcohol in the stomach before it enters the bloodstream. These biological differences mean women usually reach higher BAC levels than men when consuming the same amount of alcohol relative to body weight.
Alcohol metabolism varies by individual, but the average person metabolizes alcohol at a rate of about 0.015-0.017% BAC per hour. This means:
While BAC may return to zero, alcohol can be detected in urine for 12-24 hours, in breath for 12-24 hours, and in blood for up to 12 hours. Hair tests can detect alcohol consumption for up to 90 days.
Contrary to popular belief, you cannot significantly speed up alcohol metabolism. The liver processes alcohol at a relatively fixed rate regardless of:
While staying hydrated and eating food can help manage symptoms, they don't meaningfully accelerate alcohol elimination. The only effective strategy is allowing sufficient time for your body to process the alcohol naturally.
BAC (Blood Alcohol Content) measures the concentration of alcohol in your bloodstream, typically through a blood test. BrAC (Breath Alcohol Content) measures alcohol concentration in your breath using a breathalyzer. Law enforcement typically uses breathalyzers, which estimate BAC based on BrAC measurements.
The relationship between BAC and BrAC is based on a partition ratio of approximately 2,100:1, meaning the amount of alcohol in 2,100 ml of breath is equivalent to that in 1 ml of blood. This correlation can vary between individuals and testing devices, which is why blood tests remain the gold standard for legal purposes.
Yes, certain medications can interact with alcohol and affect both BAC levels and how intoxicated you feel. Medications that may interact with alcohol include:
These interactions can enhance alcohol's effects, slow metabolism, or mask symptoms of intoxication without changing your actual BAC. Always consult your doctor about potential alcohol interactions with medications.
Food significantly impacts how quickly alcohol enters your bloodstream. When you drink on an empty stomach, alcohol passes directly through your stomach and into your small intestine, where it's rapidly absorbed into your bloodstream. This leads to a quicker rise in BAC and stronger effects.
Eating before or while drinking, especially protein-rich and fatty foods, slows the emptying of your stomach, delaying alcohol absorption and reducing peak BAC levels. This is why our calculator includes food consumption as a factor in its calculations.
While food can slow absorption, it doesn't reduce the total amount of alcohol that eventually enters your system—it simply spreads the absorption over a longer period, resulting in a lower peak BAC.