Alcohol BAC Calculator

Widmark Formula:

\[ BAC = \left( \frac{Drinks \times 5.14}{Weight \times r} - 0.015 \times Hours \right) \times 100 \]

Number of Drinks:

Weight:

lbs

Gender:

Hours Since First Drink:

hours

Estimated Blood Alcohol Content (BAC):

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1. What is the Widmark Formula?

The Widmark formula is a mathematical equation used to estimate blood alcohol content (BAC) based on the amount of alcohol consumed, body weight, gender, and time since drinking began. It provides an approximation of BAC, which is the percentage of alcohol in the bloodstream.

2. How Does the Calculator Work?

The calculator uses the Widmark formula:

\[ BAC = \left( \frac{Drinks \times 5.14}{Weight \times r} - 0.015 \times Hours \right) \times 100 \]

Where:

\( Drinks \) — Standard drinks consumed (1 drink = 14g pure alcohol)
\( Weight \) — Body weight in pounds
\( r \) — Widmark factor (0.68 for men, 0.55 for women)
\( Hours \) — Time since first drink
5.14 — Conversion factor (grams per ounce × 100)
0.015 — Average alcohol elimination rate per hour

Explanation: The formula accounts for alcohol absorption and metabolism differences based on body composition and gender.

3. Understanding BAC Levels

Details:

0.00-0.05%: Mild impairment
0.05-0.08%: Significant impairment (illegal to drive in many countries)
0.08-0.15%: Serious impairment
0.15-0.30%: Severe impairment (risk of alcohol poisoning)
Above 0.30%: Potentially life-threatening

4. Using the Calculator

Tips:

Enter accurate drink count (1 drink = 12oz beer, 5oz wine, or 1.5oz liquor)
Use current body weight
Count hours since your first drink
Remember this is only an estimate - individual metabolism varies

5. Frequently Asked Questions (FAQ)

Q1: Why is the formula different for men and women?
A: Women generally have higher body fat percentage and less water content, leading to higher BAC from the same amount of alcohol.

Q2: How accurate is this calculator?
A: It provides a reasonable estimate but individual factors like metabolism, food intake, and medication can affect actual BAC.

Q3: What's considered a "standard drink"?
A: In the US, one standard drink contains about 14 grams of pure alcohol (12oz beer, 5oz wine, or 1.5oz distilled spirits).

Q4: How long does alcohol stay in your system?
A: The liver processes about one standard drink per hour on average, but this varies by individual.

Q5: Is it safe to drive after drinking?
A: The only safe BAC for driving is 0.00%. Impairment begins with the first drink.