BAC Calculator
Estimates blood alcohol content using the Widmark formula: BAC = (alcohol_grams / (weight_kg × gender_factor × 10)) - (0...
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How It Works
Estimates blood alcohol content using the Widmark formula: BAC = (alcohol_grams / (weight_kg × gender_factor × 10)) - (0.015 × hours). This is an estimate — individual metabolism varies.
Quick Reference
2 beers, 70kg, 2hr
Widmark formula
~0.03% BAC
4 beers, 70kg, 2hr
Widmark formula
~0.06% BAC
Legal limit US
DUI threshold
0.08% BAC
Tips & Shortcuts
Legal BAC limit is 0.08% in most US states and 0.05% in most of Europe.
Food slows alcohol absorption significantly.
BAC decreases at approximately 0.015% per hour regardless of coffee, food, or cold showers.
Common Mistakes
Trusting this estimate to make driving decisions
This is an approximation. Individual metabolism varies. If in doubt, do not drive.
Thinking eating after drinking reduces BAC
Eating BEFORE drinking slows absorption. Eating after has minimal effect on existing BAC.
Frequently Asked Questions
In the US, the legal limit is 0.08% BAC for drivers 21 and over. Utah is 0.05%. Commercial drivers are limited to 0.04%. Drivers under 21 face near-zero-tolerance limits.
The body eliminates approximately 0.015% BAC per hour — about one standard drink per hour. Coffee and food do not speed this. Time is the only sobering factor.
One US standard drink: 12 oz regular beer (5% ABV), 5 oz wine (12% ABV), or 1.5 oz distilled spirits (40% ABV). Craft beers often contain 2–4 standard drinks.
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