How BAC Is Calculated
This calculator uses the Widmark formula to estimate BAC:
BAC = (Alcohol in grams / (Body Weight in grams × r)) × 100 − (0.015 × Hours)
Where r = 0.73 for males and 0.66 for females (Widmark factor for body water ratio).
Legal Limits
- United States: 0.08% BAC (0.04% for commercial drivers)
- Most of Europe: 0.05% BAC
- Zero tolerance states: Under 21 = 0.00-0.02%
Frequently Asked Questions
How long does it take to sober up? Your body metabolizes alcohol at roughly 0.015% BAC per hour. There's no way to speed this up — coffee, water, and food don't reduce BAC faster.
Is this calculator accurate enough to determine if I can drive? No. Individual metabolism varies widely. This is only an estimate. If you've been drinking, use a rideshare or designated driver.