How the bAC Calculator works
The Widmark formula divides the alcohol you consumed by the water-containing portion of your body weight, then subtracts what your liver has already cleared, about 0.015% per hour for most people. Real BAC varies with food, medications, and individual metabolism, so treat every output as a rough educational estimate.
BAC% = alcohol grams ÷ (weight × r) × 100 − 0.015 × hours
Never use any calculator to decide whether you are safe or legal to drive. Impairment starts far below 0.08%, individual results vary widely, and the only safe BAC behind the wheel is zero. If you have been drinking, arrange a ride.
Frequently asked questions
How long until my BAC is zero?
The liver clears roughly 0.015% per hour, about one standard drink, and nothing speeds it up. Coffee and cold showers make an alert drunk person, not a sober one.
Why do the same drinks affect people differently?
Body water differs with size, sex, and composition, and food in the stomach slows absorption. Two people matching drinks can sit at very different BACs.
What are the legal limits?
0.08% for drivers 21 and over in nearly all US states (0.05% in Utah), with near-zero tolerance for drivers under 21 and stricter limits for commercial drivers. Penalties begin below the limit when impairment is shown.