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BAC Calculator Illinois:
Know Your Limits

Understanding your Blood Alcohol Concentration (BAC) is crucial whether you’re planning a night out or navigating a DUI charge. Even a small amount of alcohol can impact your judgment, reaction time, and legal standing if you’re pulled over. Our BAC Calculator provides an estimate based on key factors like weight, biological sex, number of drinks, and time elapsed, helping you make informed decisions. While this tool is for informational purposes only, it highlights just how quickly alcohol can affect your system—and why it’s always safest to plan ahead.

Illinois BAC Limits

Drivers Under age 21: 0 (Zero Tolerance)
School Bus Drivers: 0 (Zero Tolerance)
Commercial Driver’s License Holders: 0.04 BAC
Drivers age 21+: 0.08 BAC

For BAC limits & more, see the Illinois DUI Factbook 2025 from the Secretary of State.
This is for information only, not legal advice.

BAC Calculator

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