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How does a BAC calculator work?

Blood alcohol content (BAC) calculators, primarily found online or via smartphone apps, offer a way to estimate how drunk you are based on how many drinks you have had and a number of biological factors. These estimates are fairly reliable for a lot of people, but they have plenty of limitations.

Keep reading to learn how they work, what information they consider, and their limitations. And most importantly, do not rely on them to estimate if you are okay to drive after drinking. Just call a cab instead.

What is BAC?

Cocktails at a BarFirst, know what BAC is.

Basically, BAC is the amount of alcohol in your blood. It is the mass of alcohol per volume of blood. If there are 0.08 grams of alcohol per 100 grams of blood, your BAC would be 0.08 percent.

In Ohio, it is illegal to drive with a BAC of:

  • 08 percent for adults 21 and over
  • 02 percent for those under age 21
  • 04 percent for commercial drivers

How do I use a BAC calculator?

BAC calculators and charts provide a rough estimate of how many drinks it might take you before you reach the legal limit. Different BAC calculators require different information. Most consider these factors:

  • Number of drinks you’ve consumed
  • Types of drinks you’ve consumed
  • Time spent drinking (over how long did you consume the drinks?)
  • Body weight
  • Gender

But remember, alcohol content and the size of each drink can vary widely. “One drink” often refers to:

  • Beer: 12 ounce can, bottle, glass
  • Wine: 5 ounce glass
  • Spirits: 1.5 ounce shot

But anybody who has ever consumed alcohol knows that these are imprecise measures. Some beers have higher alcohol content than others. Some shots have more liquor than others. Some mixed drinks have several different types of liquor in various quantities.

And this is just one limitation of BAC calculators.

What are other limitations of BAC calculators?

Remember that BAC relies on a number of biological factors, so it is important not to use the BAC calculator to determine if you should drive after drinking. Even the most well rounded calculators cannot possibly account for all of the variables that could alter the way your body metabolizes alcohol at any given time. This can include:

  • Genetics
  • Body fat percentage
  • Health
  • How much you have eaten
  • Alcohol content of the beverage

In addition, human error can also play a role in inaccurate or misleading results. As you consume more alcohol, it becomes more difficult to accurately input information into the calculator. This in and of itself can lead to inaccurate results.

Facing an OVI arrest?

Do not rely on BAC calculators to estimate your ability to drive after consuming alcohol. Instead, call a cab, Uber, or find alternate transportation if you’ve been drinking.

But if you are facing drunk driving charges in Cincinnati, Ohio, DUI defense attorneys at The Farrish Law Firm, L.P.A. can help. Contact us at 513-621-8700 today to schedule your initial consultation.

Learn more about DUI penalties in Ohio.