Online BAC Calculator

Blood Alcohol Content (BAC) is the percentage of alcohol in your bloodstream by volume. A BAC of 0.08% means there are 0.08 grams of alcohol per 100 milliliters of blood. BAC is the standard measure used legally and medically to determine intoxication. In most US states and many countries worldwide, 0.08% is the legal limit for driving.

This calculator uses the Widmark formula: BAC = (alcohol consumed in oz × 5.14) ÷ (body weight in lbs × r) − (0.015 × hours). The "r" factor is 0.68 for men and 0.55 for women, reflecting differences in body water distribution. While widely used, the formula provides estimates — actual BAC varies based on individual metabolism, food intake, and other factors.

It varies by weight, sex, and drinking speed. As a rough guide: a 160-lb male typically reaches 0.08% after about 4 standard drinks in one hour, while a 140-lb female may reach it after about 3 drinks. A "standard drink" is 12 oz of beer (5% ABV), 5 oz of wine (12% ABV), or 1.5 oz of liquor (40% ABV). Use the reference charts on this page for more specific estimates.

Your body eliminates alcohol at an average rate of 0.015% BAC per hour — and nothing can speed this up. At a BAC of 0.08%, it takes roughly 5.5 hours to reach 0.00%. At 0.15%, expect about 10 hours. Coffee, water, cold showers, and exercise do not accelerate the process. Only time works.

No. These are persistent myths. Caffeine can make you feel more alert, and a cold shower might jolt you awake, but neither has any effect on your blood alcohol level. Your liver metabolizes alcohol at a fixed rate of approximately 0.015% per hour, and nothing can change this rate.

In the US, one standard drink contains approximately 0.6 oz (14 grams) of pure alcohol. This equals about 12 oz of regular beer (5% ABV), 5 oz of wine (12% ABV), or 1.5 oz of distilled spirits (40% ABV). Be aware that many craft beers, large wine pours, and cocktails contain significantly more than one standard drink.

Women typically have a higher percentage of body fat and lower percentage of body water than men of the same weight. Since alcohol is water-soluble, it becomes more concentrated in women’s blood. Women also tend to produce less alcohol dehydrogenase, the enzyme that breaks down alcohol in the stomach, meaning more alcohol enters the bloodstream intact.

Yes, but timing matters. Eating before or during drinking slows alcohol absorption from your stomach, resulting in a lower peak BAC. High-protein and fatty foods are most effective. However, eating after you’ve finished drinking has minimal effect since most alcohol has already been absorbed into your bloodstream.

No. This calculator provides estimates based on average metabolism. Your actual BAC depends on many individual factors including food intake, medications, hydration, liver health, and genetics. Even a BAC below the legal limit can impair your driving ability. If you’ve been drinking, use a designated driver or ride service.

Both refer to impaired driving offenses, but the terms vary by US state. DUI (Driving Under the Influence) and DWI (Driving While Intoxicated) may be used interchangeably or indicate different severity levels depending on jurisdiction. In some states, DWI is the more serious charge. Regardless of terminology, driving at or above 0.08% BAC is illegal in all 50 states.

Risk increases significantly at BAC levels above 0.20%, with acute danger at 0.30% and above. Symptoms include confusion, vomiting, seizures, slow or irregular breathing, blue-tinged skin, and loss of consciousness. A BAC above 0.40% is frequently fatal. If someone shows these signs, call 911 immediately — do not wait for them to “sleep it off.”