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If you have been pulled over by a police officer after you were drinking alcohol, you could be facing some serious consequences. The acronyms BAC and BrAC might have been thrown around, and you don’t understand them.

Here are some questions that you should know the answers to if you are facing charges for a DUI or DWI.

What does BAC stand for, and what is BAC meaning?

Your “blood alcohol concentration” (also known as “blood alcohol content”), which is often abbreviated BAC, is the percentage of alcohol that you have in your bloodstream.

What determines your BAC?

There are several factors that determine your BAC. These include:

  • Your weight
  • Your gender
  • How much alcohol you consumed
  • Over what period of time did you drink the alcohol
  • Any medications that you may be taking that could affect how your body metabolizes the alcohol

So, what does BrAC stand for?

BrAC is considered a person’s breath alcohol concentration. It is measured by breathing into a breathalyzer or any similar breath tester. Most devices convert your BrAC result into your BAC result.

How does your BrAC determine your BAC?

The reason why a breathalyzer can figure out your BAC from a single breath that you exhale is simple. Your blood (which has alcohol in it) passes through your lungs to provide it with oxygen. This alcohol evaporates during the breathing process and is expelled through the mouth, which is why you can smell alcohol on someone’s breath.

The breathalyzer uses sensors to analyze the air that you are exhaling, which is filled with alcohol, allowing it to measure your BrAC, which can then be converted to a BAC measurement (see below).

Can you convert your BrAC to BAC if the breathalyzer doesn’t do it for you?

If you have a breathalyzer that doesn’t convert the BrAC measurement to a BAC measurement, you can easily do it yourself.  The ratio between BrAC to BAC is 2100:1, which means that for every 2100 milliliters of air in the breath, it will have the same alcohol content as one milliliter of blood in the body.

When talking about your BAC, your number will often be expressed in grams of alcohol in one hundred milliliters of blood. BrAC is often expressed as the number of milligrams of alcohol in one liter of air.

How are BAC and BrAC the same?

  • Many times BAC and BrAC seem to be used interchangeably. Most people use BAC as an alcohol concentration metric. The term BrAC is usually used when referring to breathalyzer test results.
  • These terms describe how much alcohol a person has consumed, and to determine if a driver is too impaired to operate a vehicle safely.

How are they different?

Although the BAC may seem more accurate, the BrAC is also a reliable measurement and is easier to get when you are dealing with someone who shouldn’t be driving. A breathalyzer test given by a police officer can quickly determine if someone is too impaired to drive.

For a police officer to get a BAC, the driver would typically have to be taken into a hospital to get their blood drawn, which can take time and may decrease the alcohol level as the person sobers up.

BrACs are also helpful for ignition interlock devices. If you were convicted of a drunk driving offense, you might need to breathe into a device to ensure that you are sober before your car starts.

If you need a reliable ignition interlock device that will give you accurate, reliable results of your breath alcohol concentration (BrAC,) you can trust in RoadGuard Interlock. Don’t hesitate to contact us today!


*Links to any third-party websites herein are provided for your reference and convenience only. RoadGuard Interlock did not create nor develop and does not own any such third-party websites. RoadGuard Interlock does not endorse nor support the content of, nor any opinions stated in any such third-party website links. RoadGuard Interlock is not responsible for the content of any third-party website or its accuracy or reliability. Nothing contained in this article or in any such third-party website shall be considered legal advice or be deemed to constitute legal advice. For any legal advice concerning a DUI arrest, charge, conviction, or consequences thereof, you should contact an attorney of your choice.