Blood Alcohol Concentration (BAC) Calculator

Calculate Your Blood Alcohol Concentration (BAC) Calculator

About Blood Alcohol Concentration

Blood Alcohol Concentration (BAC) is a measure of the amount of alcohol in a person's bloodstream. It is expressed as a percentage, representing grams of alcohol per 100 milliliters of blood.

How BAC is Calculated

The calculator uses the Widmark formula, which takes into account:

Gender (affects body water content)
Body weight
Number of drinks consumed
Alcohol content of each drink
Volume of each drink
Time elapsed since drinking began

BAC Levels and Effects

Different BAC levels have varying effects on the body:

0.02-0.05%: Mild relaxation, slight euphoria
0.05-0.08%: Reduced coordination and alertness
0.08-0.15%: Impaired balance, speech, vision, and judgment
0.15-0.30%: Major impairment, possible nausea, confusion
Above 0.30%: Loss of consciousness, potential life-threatening effects

Note: This calculator provides estimates only and shouldn't be used to determine if you're fit to drive. Many factors affect individual BAC beyond what this calculator accounts for, including medications, health conditions, and individual metabolism.

Frequently Asked Questions

This calculator provides an estimate based on the Widmark formula, which is widely used but has limitations. Individual factors like metabolism, food consumption, and medications can affect actual BAC levels. For legal or medical purposes, only proper testing by professionals should be relied upon.

A standard drink typically contains about the same amount of pure alcohol: 14 grams (0.6 ounces). This equates to roughly 12 oz of beer (5% alcohol), 5 oz of wine (12% alcohol), or 1.5 oz of distilled spirits (40% alcohol). In this calculator, you can specify the exact volume and alcohol content.

On average, the body metabolizes alcohol at a rate of about 0.015% BAC per hour. For example, if your BAC is 0.08%, it would take approximately 5.3 hours to reach 0%. However, this rate varies between individuals based on factors like metabolism, liver function, and body composition.

Women generally have a higher percentage of body fat, less body water, and lower levels of alcohol dehydrogenase (an enzyme that breaks down alcohol) compared to men of similar weight. These factors mean alcohol is less diluted in women's bodies and metabolized more slowly, resulting in higher BAC levels.

No, you should never use this or any online calculator to determine if you're fit to drive. The only safe approach is to avoid driving completely if you've consumed any alcohol. Even BAC levels below legal limits can impair driving ability.