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Blood Alcohol Calculator
Calculate your blood alcohol concentration based on the Widmark formula.
| BAC range | Effect |
|---|---|
| 0.0 ‰ | No impairment |
| 0.1–0.3 ‰ | Slight disinhibition, feeling of warmth |
| 0.3–0.5 ‰ | Reduced reaction time, elevated mood |
| 0.5–1.1 ‰ | Noticeable impairment of coordination and reaction time |
| 1.1–2.0 ‰ | Severe balance issues, slurred speech |
| > 2.0 ‰ | Impaired consciousness, life-threatening |
How it works
This calculator uses the Widmark formula: Alcohol (g) = Volume × (ABV / 100) × 0.8. BAC = Alcohol (g) / (Body weight × r), where r = 0.68 (men) or 0.55 (women). Elimination rate is approximately 0.15‰ per hour. This is an estimate — individual factors may vary.
Frequently Asked Questions
How is BAC calculated?+
Using the Widmark formula: alcohol (g) / (body weight × r). r = 0.68 for men, 0.55 for women. This estimate is medically established but varies individually.
How fast does the body metabolize alcohol?+
About 0.015–0.02 % per hour, on average 0.015 % BAC. Metabolism cannot be sped up by coffee, water, or exercise.
What are the legal BAC limits?+
Most U.S. states: 0.08 % BAC. Many European countries: 0.05 %. Germany: 0.05 %. New drivers and under 21: typically 0.00 %. Always check local law.
Why is the estimate imprecise?+
Individual factors like stomach contents, liver function, sex, medications, and body composition can shift the real value by ±20–30 %.
Are women more sensitive to alcohol?+
Yes. Women on average have lower body water and reduced alcohol dehydrogenase activity. For the same intake, BAC is higher.
When is it safe to drive again?+
Only at 0.00 % BAC. After reaching 0.10 %, full clearance takes about 6–7 hours. Residual alcohol the next morning is common — even after 8 hours of sleep.
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