Blood Alcohol Content (BAC) Calculator — United States

All 50 US states set the per se DUI limit at 0.08% BAC for drivers 21 and over. Utah lowered its limit to 0.05% in 2019. Commercial drivers (CDL) face a 0.04% federal limit. Drivers under 21 face zero-tolerance laws ranging from 0.00% to 0.02% depending on the state.

DUI (Driving Under the Influence) and DWI (Driving While Intoxicated/Impaired) are used interchangeably in different states. Some states use both terms with different meanings — in Texas, DWI is the primary offence while DUI applies specifically to minors. The key point: any BAC at or above 0.08% (or 0.05% in Utah) creates a per se presumption of impairment.

Yes. Prosecutors can charge DUI based on observed impairment regardless of BAC. If an officer observes poor driving, slurred speech, or failed sobriety tests, you can be convicted even with a BAC below 0.08%. Some states also have 'driving while ability impaired' (DWAI) charges for BAC between 0.05% and 0.07%.

The average person metabolizes approximately 0.015% BAC per hour. Individual rates vary based on liver enzymes, medications, food consumption, and genetics. At 0.16% BAC, it takes approximately 7 hours to reach 0.05% and over 10 hours to reach zero. No food, coffee, or water speeds up this process.