BAC Calculator
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Results (BAC Estimate)
| Estimated BAC | — |
|---|---|
| Impairment Status | — |
How Blood Alcohol Concentration (BAC) is Estimated
Blood Alcohol Concentration (BAC) measures the percentage of alcohol present in a person's bloodstream. It is estimated using the **Widmark formula**, which relates body mass, gender-based body water coefficients, alcohol quantity, and rate of metabolic clearance over time.
The Widmark Formula
The Widmark equation is defined as:
- $$\text{BAC (\%)} = \left( \frac{\text{Alcohol consumed (grams)}}{\text{Body weight (grams)} \times r} \times 100 \right) - (\beta \times \text{Hours})$$
Where:
- **$r$ (distribution ratio):** $0.68$ for males, $0.55$ for females (reflecting average muscle-to-fat differences).
- **$\beta$ (clearance rate):** Estimated average of $0.015\%$ alcohol elimination per hour.
- **Standard Drink:** In the US, a standard drink contains exactly **14 grams** of pure ethanol.
Disclaimer. This calculator provides mathematical projections only. Real-world sobriety, impairment, and BAC levels depend on food consumption, medications, liver health, genetics, and hydration. **Never use mathematical calculations to determine safety for driving or operating machinery.**