How Long Does Alcohol Stay In Your System?

Quick Answer with Calculation:

An average healthy person can metabolize: 1 unit of alcohol every hour. But a large consumption can take longer.

(1 pint lager OR 1 glass of wine is about: 2.5 units of alcohol)

The method & calculation to metabolize alcohol from the body:

  • 8 units or below:
    its (No. of units + 1 hour)

    For example: (2 pints lager / 2 glasses of wine = 5 units, which would take approximately: 6 hours)

  • 9-11 units or below:
    its (No. of units + 1.5 hours)

    For example: (4 pints lager / 4 glasses of wine = 10 units, which would take approximately: 11.5 hours)

  • Over 12 units:
    its (No. of units x 1.5 hour)

    For example: (6 pints lager / 6 glasses of wine = 15 units, which would take approximately: 22.5 hours)


(information based on normal strength lager of 4% ABV – or –   175ml glass of wine of 13% ABV)
However, if taking a urine test for employment purposes, then small traces of alcohol can be detected within the urine for about: 12 to 24 hours since last consumption.



How Long Does Alcohol Stay In Your System
Chart showing the No. of hours to clear the
No. of consumed units of alcohol from the body.


How Long Does Alcohol Stay In Your System?

Long Answer:

It is not that uncommon for people to feel the hit after a hard night of partying, thanks to the raging hangover caused by all that alcohol consumed the night before. However, the situation can get even trickier if you happen to have had quite a few drinks while partying but have to appear for an alcohol test the morning after. It is during times like these that most of you must have wondered about how long does alcohol stay in your system. Having the answer to this query is important because it will help you in planning your alcohol consumption the next time you have to face any such alcohol test the very next day after a big night out, or any major celebrations involving drinking copious amounts of beer, wine, and other forms of alcohols. However, the urban myth regarding the weight or gender of a person deciding the rate of alcohol metabolism is untrue and it is same for all. However, gender and size does have a role on the severity and duration of the effects of alcohol on the body.

However, the answer to the common question which is how long does alcohol stay in your body, is quite complex to tell you the truth. This is because the human body works to eliminate an intoxicating substance such as alcohol in several levels. Thus, you can expect your body to eliminate a portion of your total alcohol intake through the normal excretory system of the body such as sweat, urine, and breath. However, this portion adds up to a merely 10% of the total alcohol intake, and rest has to depend upon the working of the liver for their breakdown and excretion from the body. This knowledge will surely help you in realizing that there is no shortcut to eliminating the alcohol from your body without allowing the normal processes to run their course.

A healthy individual is capable of eliminating around 10 ml of pure alcohol from his or her system every hour based on the amount of alcohol consumption (See calculations at the top). Therefore, now you can roughly guess the answer to the query regarding how long does alcohol stay in system. This 10 ml of pure alcohol roughly approximates to around one unit of alcohol. For 1 pint of lager OR 1 glass of wine, which is about 2.5 units of alcohol, it would take 2.5+1= 3.5 hours to metabolize the alcohol. For those of you willing to keep your blood alcohol content to the bare minimal need to watch out for the amount of alcohol you consume, and it must never cross a single unit of alcohol every hour. However, you must always keep in mind that a single unit of alcohol does not correspond with equal measure of different types of drinks on offer. Thus, one unit corresponds to a single measure of spirit, and half a pint of low strength cider or beer, while a standard glass of average strength wine equals a couple of unit of alcohol. You need to keep these measures in your mind while drinking, and pace your drinks accordingly to ensure that your consumption does not cross the threshold of one unit of alcohol every hour.

Blood Alcohol Content (BAC):

In order to gain a more comprehensive and in-depth knowledge about the significance of the information about how long does alcohol stay in the body, you need to first gain adequate insight into the concept of Blood Alcohol Content or BAC. This is because all diagnostic tests used to find out about the level of alcohol present in the body of a person use this perimeter to quantify their results. The principal behind it is that a person having 5 parts of alcohol for every 10,000 parts of his blood has a BAC of 0.05%. It is possible to detect this level by analyzing a range of samples such as breath, urine, and blood. However, analyzing the blood sample of any person is usually the most preferred choice for availing confirmed result of the blood alcohol level for that person.


Alcohol Metabolizing Rate in Blood:

Apart from gaining information about the concept of blood alcohol content, it is equally important that you gain insight into the rate at which the body clears alcohol from the system to lower that level. The rate at which the human body metabolizes alcohol and removes it from the system is about 0.15 of BAC per hour. Thus, if a person does not drink for a couple of hours, then the body will automatically bring the BAC level down by 0.30 percent. Therefore, a person who had a BAC level of 0.50 percent will take around three hours and twenty minutes to clear the alcohol out of their system. Thus, now you can do the calculation yourself about how long does alcohol stay in your system. You can pace your drink accordingly to ensure that you do not flunk the alcohol test next day, or get hauled up for drinking under the influence of alcohol. However, always keep in mind that in case of bouts of severe binge drinking, the alcohol can stay in your system for 24 hours after you stopped drinking or even more. The more important point to keep in mind that not how long have you been drinking but how much.

The test procedure for calculating BAC involves drawing of blood, and then measuring of alcohol content every half hour. The process initiated by the body for metabolizing alcohol decides the duration of how long alcohol stays in the body. 90% of the alcohol consumed makes it way to the epithelial cells of the stomach, as well as, lower intestines, and then to the blood capillaries. The absorption of alcohol causes the classical after-effects of alcohol consumption such as blurry vision, and loss of agility of the limbs, as well as, clouded judgment. This makes undertaking of any critical task requiring fine judgment such as driving or operating heavy machineries a strict no-no till the blood alcohol level has come down to acceptable standards. Its final destination is the liver, where in the presence of the enzyme alcohol dehydrogenase ethyl alcohol is broken down into acetaldehyde. This acetaldehyde is further broken down into acetic acid or vinegar, after which is it no longer poses a threat to the body.


Factors to Consider:

While considering how long does alcohol stay in your body, you need to keep in mind that this delicate calculation hinges itself upon a number of crucial factors. These factors include the weight and gender of the person concerned, as well as, the amount of alcohol consumed, and the time elapsed since it was last consumed. The BAC of a person depends upon their gender, and thus it would be better if you follow your drinking pattern while keeping your gender in mind. The truth, at the risk of sounding gender insensitive, is that the alcohol stays for a longer duration in the system of a woman compared to a man, and this is partially because of the action of certain hormones in women. Moreover, there’s a lower percentage of water in the system of women, when compared to their male counterparts, which means that they are bound to hit a certain BAC level after having consumed comparatively lower amount of alcohol than the any man with same body weight has.

Apart from the gender, the effects of same amount of alcohol in the body are bound to differ according to their size and weight. Thus, a person weighing only a 100 pound is bound to feel greater effect after drinking a certain amount of alcohol compared to a man double his bodyweight having drunk the same amount. This is because the greater amount of water in the body of a bigger person helps in diluting the alcohol and lessening its effects. Moreover, age also plays a role with advanced age slowing down the rate of metabolism, which impedes the rate at which the body is able to breakdown and rid the body of alcohol present in the system. Thus, the answer to the query about how long does alcohol stay in your system will depend to an extent upon your gender, bodyweight, and age.

Finally, certain ailments (disorders) such as the one to the vital organs of liver or kidney can seriously compromise with the rate of alcohol detoxification. Similarly, certain medications such as paracetamol, aspirin, and pyrazole compounds can slow down the rate of alcohol detoxification. On the other hand, eating protein-rich food can help in slowing down absorption of alcohol by the body, while diluting it with water can also have the same desired effect. Thus, a number of factors act in unison to provide answer to your query about how long does alcohol stay in your body.
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