Blood Alcohol Concentration (BAC) Calculator

Widmark Formula:

\[ BAC = \left(\frac{\text{grams of alcohol}}{\text{weight} \times r}\right) \times 100 \]

Estimated Blood Alcohol Concentration (BAC):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Blood Alcohol Concentration?

Blood Alcohol Concentration (BAC) is a measure of the amount of alcohol present in a person's bloodstream. It's expressed as a percentage representing grams of alcohol per 100 milliliters of blood. BAC is used to determine legal intoxication levels and assess impairment.

2. How Does the Calculator Work?

The calculator uses the Widmark formula:

\[ BAC = \left(\frac{\text{grams of alcohol}}{\text{weight} \times r}\right) \times 100 \]

Where:

\( grams\ of\ alcohol \) — Total alcohol consumed in grams
\( weight \) — Body weight in kilograms
\( r \) — Widmark factor (0.68 for males, 0.55 for females)

Explanation: The formula estimates how alcohol distributes in body water, accounting for gender differences in body composition.

3. Understanding BAC Levels

Details:

0.02-0.03%: Mild euphoria, slight relaxation
0.05-0.06%: Reduced inhibition, exaggerated behavior
0.08%: Legal limit for driving in most countries, impaired coordination
0.15%: Gross motor impairment, blurred vision
0.30%: Possible loss of consciousness
0.40%+: Potentially fatal

4. Using the Calculator

Tips:

Convert drinks to grams of alcohol (1 standard drink ≈ 14 grams)
Use actual body weight in kilograms
Select correct gender for accurate Widmark factor
Remember this is an estimate - many factors affect actual BAC

5. Frequently Asked Questions (FAQ)

Q1: Why are there different Widmark factors for men and women?
A: Women typically have higher body fat percentage and less body water, leading to higher BAC from the same amount of alcohol.

Q2: How accurate is this calculation?
A: It provides a rough estimate. Actual BAC can vary due to metabolism, food intake, medication, and individual differences.

Q3: How long does alcohol stay in your system?
A: The body metabolizes alcohol at about 0.015% BAC per hour on average, but this varies by individual.

Q4: Can I use this to determine if I'm safe to drive?
A: No. Impairment begins at levels below legal limits, and many factors affect driving ability. Never drink and drive.

Q5: What's the legal BAC limit for driving?
A: In most countries it's 0.08%, but some have lower limits (0.05% or even 0.02% for certain drivers).