Blood Alcohol Content (BAC) Calculator
Calculate your estimated Blood Alcohol Concentration (BAC), sobriety time, and legal driving status using the scientifically validated Widmark formula.
Legal & Medical Disclaimer: This Blood Alcohol Content (BAC) calculator is provided for educational purposes only. Individual alcohol metabolism depends on biological factors, hydration, health, and digestion. Never use this tool to determine your legal fitness to drive. Always arrange a sober designated driver, taxi, or rideshare.
Understanding Blood Alcohol Concentration (BAC)
This calculator utilizes the internationally accepted Widmark Formula developed by Swedish physician Erik Widmark:
BAC = [Alcohol in Grams / (Body Weight in Grams ร r)] ร 100 โ (ฮฒ ร Time in Hours)
- r (Gender body water constant): 0.68 for males, 0.55 for females (women naturally have higher average body fat and lower body water percentage).
- ฮฒ (Elimination / Metabolism rate): The average forensic rate is 0.015% per hour.
| Country / Jurisdiction | Standard Limit | Commercial / Novice Drivers |
|---|---|---|
| United States & Canada | 0.08% (0.80 g/L) | 0.04% / Zero Tolerance (0.00-0.02%) |
| United Kingdom (Eng/Wales/NI) | 0.08% (35 ยตg / 100ml breath) | 0.08% |
| Scotland, Australia, EU (France, Germany, Spain) | 0.05% (0.50 g/L) | 0.00% - 0.02% (Strict Zero Tolerance) |
| Sweden, Poland, Norway | 0.02% (0.20 g/L) | 0.02% |
| Japan, Czech Republic, UAE | 0.00% (Zero Tolerance) | 0.00% (Strictly Prohibited) |
- Myth: "Drinking strong black coffee will sober you up."
Fact: Coffee contains caffeine which may make you feel awake, but it does NOT speed up liver alcohol metabolism or lower BAC. - Myth: "Taking a cold shower clears alcohol from your system."
Fact: Cold water causes a temporary shock reflex with zero change in metabolic rate. Only time allows the liver to break down alcohol. - Myth: "Eating greasy food after drinking absorbs alcohol."
Fact: Food only delays absorption if consumed before or while drinking. Once alcohol enters your bloodstream, food has no effect on BAC.
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