BAC (Blood Alcohol Content) Calculator
Estimate blood alcohol content (BAC) based on drinks, weight, and time. For informational purposes only. A BAC (blood alcohol content) calculator estimates your BAC based on alcohol consumed, body size, and time since drinking started. BAC is affected by many factors (food, metabolism, medications, health, and measurement error), so this tool should be treated as a rough estimate only.
Inputs
Estimated BAC
Estimated BAC
0.0639
Alcohol (oz)2.4
Distribution factor (r)0.73
Time to 0.00 (hours)4.3
Uses a Widmark-style estimate with an average elimination rate of ~0.015 BAC/hour.
BAC varies widely by person, food intake, and measurement error.
How to use it
- Enter your body weight and select a distribution factor option.
- Add drinks (or total alcohol) and the time since drinking began.
- Review estimated BAC and a conservative time-to-sober estimate.
- If you’ve been drinking, do not drive—use a safe ride option.
Key formulas
- Widmark-style estimate (common form)
- BAC ≈ (A × 5.14 / (W × r)) − 0.015 × H
- A = ounces of alcohol, W = weight (lb), r = distribution ratio, H = hours since first drink.
FAQ
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Disclaimer
Estimate only. Do not use this tool to decide whether it’s safe or legal to drive or operate machinery.