How Long After Drinking Can You Pass Breathalyzer?

The rule of thumb that most people use is one hour per unit of alcohol, but this can be misleading and can give false assurances.

Breathalyzer tests use blood alcohol content (BAC) points to show how much alcohol you have in your body. Alcohol breakdown is different from individual to individual, depending on things like age, gender and metabolic rate, but on average alcohol is broken down at a rate of 20 to 30mg/dl per hour. The average rate of alcohol excretion is 0.015 BAC points per hour.

Breathalyzers work by measuring the concentration of alcohol when a person exhales, by using electrochemical fuel cell sensors, semiconductor oxide sensors or infrared spectrophotometers to calculate the percentage of blood alcohol content.

Breathalyzers are able to detect even the smallest amount of alcohol, but for the majority of people, the concern is not that they have taken alcohol, but that they are under the legal limit. In the States, a person’s BAC needs to be under 0.04 to pass the test, while 0.08 is considered to be drunk.

How many hours that must elapse before you will pass a breathalyzer is different for each person, again due to the determining factors already outlined, but as a rule of thumb, take the reading and divide it by the standard (you can get breathalyzer testing kits for your own use). So, if the test gave a BAC reading of 0.150, divide that number by the standard 0.015, which equals 10. That means that it will take 10 hours for the alcohol to get out of your system.

Because they are measuring breath, rather than blood alcohol levels directly, there are sometimes inaccurate readings because of a variety of reasons. The most accurate breathalyzers have been found to be the ones that use semiconductor oxide sensors. Of course, if there is any real doubt, blood tests can be taken.

8 hours after drinking your last drink, you should blow zero.

That is a very hard question to answer, I will try to explain. Alcohol is dissipated by the body at a rate of roughly .015% per hour, so it depends on 1) how much you have had to drink 2) what was in the drinks you consumed (I.E. A beer vs. A mixed drink will vary extensively). 3.) Your body composition.

A good rule of thumb is .015 % per hour. If you have been drinking and have to submit to a BAC test is is a good rule to give yourself 6-8 hours (again depending on the amount ingested) Hope this helps

Depends on if you drink hard liquor or beer as well as how much you drank. I failed a couple times when the night before I drank hard liquor so now I stick to beer. If I drink an 8 pack of budweiser starting around midnight and finish around 4am.... I always seem to pass by 1 or 2.. Maybe you could sooner but better safe than sorry. Could also depend on your weigh.

There are many variables that play a part in the metabolism of alcohol, some being weight, gender, alcohol use history, amount consumed over what duration. Given that the consequences of drunk driving are harsh and it is also dangerous I would invest in a pocket Breathalyzer which are under $20. The "old school" rule was that it takes one hour for 8-ounces of an alcohol beverage to be metabolized by the liver, but take it from me that does not apply to everyone. I can have two glasses of wine over a two hour duration and be legally impaired. Better to be safe than sorry. I learned the hard way.

Rule of thumb: 3 hours per beer. To totally leave your system. Caffiene, food, etc, Will not help speed the process.

This depends on how much you have drunk in one session. 2 pints is over the legal drive limit ,that would be clear in around 6 hours. If you've downed a stupid amount say 20 beers, you would have to wait a 24 hour period from the last sip to be clear.

Don't drink and drive, give yourself 24 hours.

20 mins  lol

It can take up to 24 hours.

For everybody thinking that this question only related to drinking and driving- you're all idiots.

Some may be subject to a breathalyzer because of being on probation, or are simply just curious.

Also, people don't decide "tonight I'm driving drunk". It's usually a choice made at the hand of alcohol (STILL NOT OK) lol

Immediately … 'cause I don't drink alcohol.

Typically, you'll fail with 4 units of alcohol in your system (1 unit = 1/2 pint of beer), and you can absorb about 1 unit per hour, so you do the math.

Hey if it doesn't show on a Breathalyzer than that means it's out of your system, thus not affecting you... So it's not really driving drunk
but I also agree that driving drunk is retarded

That all depends on how much beer you consume, and you should be driving drunk anyway so I hope you get caught