Definition - What does Burn Off mean?
Burn off is the rate at which alcohol leaves the body after being ingested. The burn off is different for each person. It depends on gender and weight as well as what type of alcohol is consumed. The general formula for determining what the burn off rate, or for determining how much burn off has occurred, is generally body weight multiplied by blood alcohol level multiplied by either .26 (for men) or .23 (for women). This determination is used when a person is pulled over of suspected driving while intoxicated to decide whether a person is within the legally allowable limits to drive.
Justipedia explains Burn Off
The burn off calculation is not used in every state. It is only applicable in states where there is an allowance for driving after drinking. In states that have a zero tolerance law, any consumption of alcohol before driving is deemed illegal. The calculation itself has been under scrutiny for being too difficult to measure accurately; other forms of measurement are being developed.