Understanding blood alcohol concentration (BAC) is important for personal safety and responsible decision-making. BAC measures the percentage of alcohol present in an individual's bloodstream. For example, a BAC of 0.08% means there is 0.08 grams of alcohol for every 100 milliliters of blood.
This calculator uses the Widmark formula, a standard mathematical model developed by Swedish physician Erik Widmark. The equation factors in gender, weight, alcohol consumed, and metabolism over time: - **BAC = [ (Alcohol Consumed in grams / (Body Weight in grams × r)) × 100 ] - (Beta × Time)** - **r (Gender constant):** 0.68 for males (who typically have a higher percentage of water), and 0.55 for females (who typically have a higher fat-to-water ratio). - **Beta (Elimination rate):** The rate at which the body burns alcohol, typically averaging 0.015% per hour.
Calculations are based on "standard drinks," which in the United States contain exactly 14 grams (0.6 ounces) of pure alcohol: - **12 ounces of regular beer** (typically 5% alcohol by volume). - **5 ounces of wine** (typically 12% alcohol by volume). - **1.5 ounces of distilled spirits** (80 proof, typically 40% alcohol by volume).
If you need to perform volume or weight conversions, check out our standard measurement conversions tool.
Many variables alter how quickly alcohol enters and leaves your system: - Stomach Content: Eating food before drinking slows down the absorption of alcohol into your bloodstream. - Body Composition: Muscle tissue contains more water than fat tissue, helping to dilute alcohol. - Metabolic Rate: While the average elimination rate is 0.015% per hour, liver metabolism varies between individuals.
**IMPORTANT:** This tool provides mathematical estimations for educational purposes. It does not replace physical blood or breath tests. Never use this calculator to decide if you are safe to operate a motor vehicle. If you have been drinking, always arrange a designated driver or use rideshare services.
Alcohol consumption affects hydration levels, athletic recovery, and protein synthesis. It acts as a diuretic, increasing dehydration risks during subsequent workouts, and can disrupt sleep cycles, reducing growth hormone production.
To manage daily nutrient goals for sports recovery, explore our macronutrient ratios helper and check our protein calculator. To track workout paces, try our pace calculator.
Your body metabolizes alcohol through the liver using enzymes like alcohol dehydrogenase. This process takes priority over other metabolic pathways, meaning fat burning is temporarily reduced while your body works to clear alcohol from your system.
Clearance is not reliably accelerated by coffee, a cold shower, food eaten after drinking, or exercise. Those actions may change how alert a person feels without removing alcohol from the bloodstream. Body size, biological sex, drinking pace, meal timing, medications, liver health, and the actual pour size all introduce uncertainty into an estimate. Mixed drinks and large glasses frequently contain more than one standard drink. Because impairment can remain after the estimated value falls, the safe transportation decision is to avoid driving and use a sober driver, taxi, or rideshare.