Blood Alcohol Calculator

How is Blood Alcohol Content (BAC) Calculated?

Blood Alcohol Content (BAC) estimates the concentration of alcohol in a person's bloodstream. It's influenced by several factors, including body weight, gender, the amount and type of alcohol consumed, and time elapsed since drinking.

The most common formula for estimating BAC is the Widmark formula:

BAC = (Alcohol Consumed in grams / (Body Weight in grams × r)) × 100 - (Metabolism Rate × Hours)

Parameters Explained

  • Weight (kg): Your body weight in kilograms.
  • Number of Drinks: Total number of alcoholic drinks consumed.
  • Alcohol by Volume (ABV %): The percentage of alcohol in your drink (e.g., beer is typically 5%).
  • Drink Volume (ml): The volume of a single drink in milliliters (e.g., a standard beer bottle is 330ml).
  • Gender: Biological sex, as body water content differs between males and females.
  • Hours Since First Drink: Time elapsed since you started drinking.

FAQs

  • How accurate is this BAC calculator?
    This calculator provides an estimate based on standard formulas. Actual BAC can vary due to metabolism, health, and other factors.
  • What is a 'standard drink'?
    A standard drink typically contains about 14 grams of pure alcohol, but this varies by country and drink type.
  • How long does alcohol stay in your system?
    On average, the body processes about one standard drink per hour, but this can vary.
  • Can I drive if my BAC is below the legal limit?
    Even if you're below the legal limit, alcohol can impair your ability to drive safely. Always use caution.
  • Does food affect BAC?
    Yes, eating before or while drinking can slow the absorption of alcohol, resulting in a lower BAC.

BAC Calculator