Your blood alcohol content, or blood alcohol concentration, (BAC) is the amount of alcohol in your blood.
It is given as a percentage of your blood. A BAC of .08 means that .08%, or eight one-hundredths of your blood is alcohol. Put that way, it doesn’t sound like much at all, but a BAC of .08 or higher will land you a DUI when driving in most states. Even if you are not driving, your BAC affects your judgement and coordination, and if it is high enough you can experience alcohol poisoning or even death.
Calculating Your BAC as You Go
Trying to calculate your BAC on the fly is risky. There are too many variables involved to do it accurately. It should go without saying that the least reliable measurement is feeling like you are not too drunk. Alcohol plays that trick on your mind. People who are impaired typically feel like they are good to go.
Everyone’s BAC rises at a different rate, for a number of reasons. Body weight, your fat content, whether or not you have eaten, and your gender can all affect how quickly your BAC rises.
Contrary to popular belief, most healthy people process alcohol out of their systems at about the same rate, regardless of size or gender. However, chronic alcoholics tend to metabolize alcohol faster, and your ability to eliminate alcohol tends to slow down as you get older. Tricks like drinking coffee to sober up may make you feel less drunk, but they do not lower your BAC any faster.
If you have been drinking, the best option is not to drive. Always have one member of your group be the designated driver. You can also purchase a portable breathalyzer to check your own blood alcohol level before driving. However, that is not recommended because it may make it easier to justify having a drink or two and once you are impaired, you may not use good judgment when deciding whether or not to drive.