BAC Calculator

In 49 US states, the statutory legal per se limit for drivers age 21 and older operating non-commercial vehicles is 0.08% BAC. Utah has a lower limit of 0.05% BAC. For commercial driver’s license (CDL) holders, the federal limit is 0.04%. Drivers under age 21 are subject to Zero Tolerance laws (typically 0.00% to 0.02%). Crucially, drivers can still be charged with driving under the influence (DUI/DWI) below 0.08% if law enforcement observes physical or cognitive impairment.

• •0.08% standard statutory limit in 49 US states
• •0.05% limit in Utah; 0.04% for commercial drivers (CDL)
• •Zero tolerance (0.00%–0.02%) for drivers under 21
• •DUI/DWI impairment citations can still occur below 0.08%

No. Online BAC calculators are strictly educational estimation tools. They rely on generalized population averages and cannot account for stomach fullness, unique metabolic variations, hydration, sleep deprivation, or medication interactions. Never use an estimated calculation to decide whether to drive.

• •Calculators rely on statistical population models, not clinical biology
• •Stomach contents and individual enzymes cause significant variances
• •Always designate a sober driver, call a taxi, or use rideshare

On average, the human liver metabolizes alcohol at a rate of approximately 0.015% BAC per hour (equivalent to roughly one standard drink per hour). This rate cannot be accelerated by drinking coffee, taking cold showers, exercising, or drinking water.

• •Standard metabolic elimination rate is β = 0.015% BAC per hour
• •Enzymes (ADH and ALDH) process alcohol at a constant zero-order rate
• •Only the steady passage of time clears circulating ethanol from blood

According to the CDC and NIAAA, one standard drink in the United States contains 14.0 grams (0.6 fluid ounces) of pure ethanol. This is typically found in: 12 fluid ounces of regular beer (~5% ABV), 5 fluid ounces of table wine (~12% ABV), or 1.5 fluid ounces of 80-proof distilled spirits (~40% ABV).

• •12 fl oz regular beer (~5% ABV)
• •5 fl oz table wine (~12% ABV)
• •1.5 fl oz 80-proof distilled spirits (~40% ABV)
• •Craft beers and cocktails frequently equal 1.5× to 3× standard drink equivalents

No. Neither coffee, exercise, cold showers, nor commercial "hangover pills" speed up liver metabolism. Caffeine may make an individual feel more alert, but their cognitive and motor impairment remains identical. Only time allows the liver to metabolize alcohol.

• •Caffeine creates a "wide-awake drunk" state without restoring reflexes
• •Enzymatic clearance rate remains fixed regardless of hydration
• •Time is the only physiological method to eliminate ethanol

Breathalyzers measure the concentration of alcohol vapor in deep alveolar lung breath and use a partition ratio (typically 2,100:1 in the US) to estimate blood alcohol concentration. While evidentiary devices are calibrated and legally recognized, certified laboratory blood draws remain the gold standard of clinical measurement.

• •Measures alveolar breath alcohol using infrared or fuel cell sensors
• •Converts to BAC using a standard 2,100:1 breath-to-blood ratio
• •Certified laboratory blood draws remain the clinical gold standard

The Widmark formula utilizes the body water distribution ratio (r) because average total body water percentage differs between males (~68%) and females (~55%). This parameter ensures the mathematical estimate reflects body water dilution accurately.

• •Biological males average ~68% total body water (r = 0.68)
• •Biological females average ~55% total body water (r = 0.55)
• •Females also typically produce less gastric alcohol dehydrogenase (ADH)

No. Your body weight, drink selections, and timeline entries exist only in your current session while you view the page. No values are recorded in databases, shared with third parties, or saved after you close the tab.

• •Inputs are processed locally in your active tab session
• •Inputs are never stored in external databases or servers
• •Closing or refreshing the page clears all session inputs