BAC Calculator: Estimate Your Blood Alcohol Concentration

Use the blood alcohol level calculator to estimate your blood alcohol concentration (BAC) for a given number of drinks.

By , Attorney · University of San Francisco School of Law

In every state, you can get a DUI (also called "DWI" and "OWI") for driving with a blood alcohol concentration (BAC) of .08% or more. For drivers under 21 years old, there are also "zero-tolerance" laws that impose much stricter BAC limits. (Also, the BAC limit is generally lower for commercial vehicle drivers than for regular motorists.)

Everyone absorbs and metabolizes alcohol at different rates, so estimating a person's blood alcohol content is difficult. And because of how "driving under the influence" is defined, even if you don't have a BAC that's above the legal limit, you can still get a DUI if you are actually impaired by drugs or alcohol while driving.

The calculator below can give you an approximation of what your BAC might be based on:

  • your gender
  • the number of drinks you've had
  • the time you've been drinking, and
  • your weight.

DUI Laws by State

Follow the links below to find out about the DUI laws in your state.

Using the BAC Calculator: A Warning

The BAC calculator gives only estimates of blood alcohol concentration based on specifically sized drinks and doesn't take into account all the factors that affect BAC or level of impairment. Relevant factors not captured by this calculator include how much you've slept, whether you've taken medications, how much you've eaten, and whether you're chugging or sipping. So you shouldn't rely on these estimates to make any decisions. If you've been drinking, let someone else drive.

      (For more information on blood alcohol concentration levels, see our BAC chart.)


      Number of Drinks

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