How Much Alcohol Is Too Much for You?

Blood Alcohol Content (BAC) Calculator

To determine your limits for drinking and driving, complete the following items, then press calculate to obtain the BAC estimate:

Gender

 

Your Consumption

  

Your Levels

 
 

What Can Affect Blood Alcohol Content (BAC)?

While the calculator can give you an idea of how much you can drink and still be sober enough to drive, there are many factors that can affect your BAC measurement, including the following:

  • Amount. The amount of alcohol is the most obvious factor, as well as the most important.
  • How quickly you consume. Four drinks within one hour, for example, will yield a higher Blood Alcohol Content than four drinks within three hours.
  • Body mass. People with higher body weights are not affected by alcohol as quickly as people with lower body weights.
  • Food in your stomach. The food in a person’s stomach will absorb some of the alcohol, reducing the rate at which it is absorbed into the bloodstream. Alcohol consumed on an empty stomach will be absorbed by the body more quickly, resulting in an increased Blood Alcohol Level.
  • Type of mixer used for mixed drinks. Alcohol is not absorbed as quickly when water and juices (non-carbonated beverages) are used to make mixed drinks. When carbonated beverages such as soda or energy drinks are used, however, the alcohol absorption rate can be quicker. Quicker absorption rates will usually lead to increased Blood Alcohol Levels.
  • Gender. Women tend to reach higher Blood Alcohol Content levels more quickly than men do. If a man and a woman consume the same amount of alcohol over a given period of time (and all other factors are held equal), the man will have a lower Blood Alcohol Level than the woman. This is because women tend to have less water and more adipose tissue in their bodies.

Tips to Maintain a Safe Blood Alcohol Level

While the legal Blood Alcohol Content in most states is 0.08, the “safe” Blood Alcohol Content for driving (as defined by many state authorities) is 0.05 or less. Use the following tips to ensure that you maintain a safe Blood Alcohol Level:

  • Do not consume all of your drinks at once. Space them out over time (e.g. one drink per hour).
  • Keep track of how many drinks you have (keeping bottle caps or cocktail straws in pants pockets are two common methods).
  • Consume food both before and during your night out.
  • Pour your own drinks whenever possible.
  • Refrain from playing drinking games.
  • Drink a variety of alcoholic and non-alcoholic drinks.
  • Avoid mixed drinks that contain caffeine or energy drinks.

Calculate Blood Alcohol Content

The most commonly used formula to calculate Blood Alcohol Content is:

%BAC = (A x 5.14/W x r) – .015 x H, where

  • “A” is the number of liquid ounces of alcohol consumed. For example, the standard 5% beer would be .60 (12 x 0.05)
  • “W” is the person’s weight in pounds
  • “r” is the distribution ratio (.66 for women, and .73 for men)
  • “H” is the number of hours in which the alcohol was consumed

Just like the calculator above, however, this formula is not 100% accurate when used to calculate Blood Alcohol Content. Several complex factors must be taken into consideration to accurately calculate Blood Alcohol Content, such as physical and emotional health, as well as the consumption of food.

BAC Calculator Disclaimer

A person’s exact Blood Alcohol Content depends on a variety of complex factors. While the above factors are the most apparent, emotional, physical, and overall health can play a role as well, in addition to the consumption of other drugs (prescription or otherwise). It is impossible for an online blood alcohol content calculator or chart to be 100% accurate. The information provided above is merely an estimate and should not be used to make decisions about drinking or driving.

If you are ever unsure of your ability to pass a breathalyzer test, do not depend on a BAC calculator. Call a taxi or phone a friend. Regardless of how expensive the taxi, it will always be less expensive than driving under the influence.

Rob Crow
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Licensed to practice law in all State & Federal Courts in Oregon.