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Estimate BAC using the Widmark formula. Enter drinks, weight, and hours to gauge impairment.
Blood Alcohol Concentration (BAC) is the percentage of alcohol in the bloodstream. A BAC of 0.08% is the legal driving limit in the US. BAC is influenced by gender, weight, drinks consumed, and time elapsed.
12 oz · 5% ABV (standard)
Current Estimated BAC
0.036%
Impairment Level
Slight impairment
⚠️ This is an estimate only. Never drive after drinking.
Formula
BAC = (drinks × 14g) ÷ (weight_g × r) − 0.015 × hoursdrinks × 14g = total pure alcohol (14g = 1 standard drink)
weight_g = body weight in grams
r = Widmark distribution factor: 0.68 male, 0.55 female
0.015 = average metabolism rate (BAC % per hour)
Worked Example
Example: 160 lb male, 3 standard beers, 2 hours elapsed
Did you know? A BAC of 0.08% impairs reaction time by up to 40% and halves your ability to track moving objects: this is why it is the legal driving limit in the United States and most of Europe.
Sources
| BAC % | Typical Effects |
|---|---|
| 0.02% | Light relaxation, slight mood elevation |
| 0.05% | Lowered inhibitions, impaired judgment |
| 0.08% | Legal DUI limit (US): significantly impaired |
| 0.10% | Slurred speech, poor coordination |
| 0.15% | Nausea, disorientation, serious impairment |
| 0.20+% | Loss of consciousness risk, life-threatening |
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