How Much Can You Drink Before You Are Affected by the Alcohol? (2024)

Your blood alcohol concentration (BAC) is what determines how intoxicated you get from drinking alcohol and varies by your sex and body weight. Also known as blood alcohol content, BAC is used for both legal and medical purposes.

Overview

In the United States, a BAC of 0.10 (one-tenth of one percent) means that there is 0.10 g of alcohol for every 100 milliliters (mL) of blood. According to the law, the legal limit for operating a motor vehicle is 0.08 for drivers 21 and over. Many states have zero-tolerance policies for drivers under the legal drinking age, which make it illegal to have a BAC over .00 if you are under 21.

Blood Alcohol in Men

Blood alcohol concentration can differ significantly between men and women, with women tending to have higher BAC than men of the same age and weight. Moreover, men are able to metabolize alcohol faster because they have higher levels of an enzyme called alcohol dehydrogenase (ADH) in their stomach and liver.

Even so, the time it takes a man to metabolize a single alcoholic beverage is not one hour, as some would have you believe. Depending on your weight, it can take far longer.

What Counts as a Drink?

One drink equals 1 12-ounce bottle of beer, 5 ounces of wine, or 1 oz of 100-proof liquor. But how intoxicated you become depends on how quickly you consume alcohol over a period of hours. For an average-sized American man, for example, drinking four beers in two hours may not be enough to raise your BAC to .08%, but five beers likely will be.

After One Drink

Most people will tell you that one drink is "no big deal." While some men may respond to a single drink with a little tipsiness, others may appear entirely unaffected. That doesn't mean that they've "cleared" the alcohol from the body; it simply means that their brains are more accustomed to alcohol and won't react as profoundly.

As a general rule, the average speed of metabolism (in which the alcohol is fully broken down and no longer present in the blood) will be slower the smaller a man is. The effects of drinking, therefore, can vary as can speed by which the BAC returns to normal. For example:

• At 100 pounds, he will have a blood alcohol concentration of 0.04 after one drink. If he drinks it over one hour, he will have a blood alcohol concentration of 0.02, and if he drinks it over two hours, he will have a blood alcohol concentration of 0.01. Only after three hours will he have a blood alcohol concentration of 0.00.
• At 150 pounds, a man will have a blood alcohol concentration of 0.03 after one drink. If he drinks it over one hour, he will have a blood alcohol concentration of 0.01, and after two hours, he will have a blood alcohol concentration of 0.00.
• At 200 pounds, a man will have a blood alcohol concentration of 0.02 after one drink. If he drinks it over one hour, he will have a blood alcohol concentration of 0.003, and after two hours, he will have a blood alcohol concentration of 0.00.

After Two Drinks

Two standard American drinks will, on average, produce a blood alcohol concentration of about 0.04, and most light and moderate drinkers will feel relaxed at this level. Even if you don't feel the effects of intoxication, your reaction times will be slowed and fine motor skills will be affected to the extent that driving will be impaired.

After two drinks, the metabolism of alcohol in men will further slow, meaning that you will have to wait longer before you get behind the wheel. For example:

• At 100 pounds, a man will have a blood alcohol concentration of 0.08 after two drinks. If he drinks them over one hour, he will have a blood alcohol concentration of 0.06, and if he drinks them over two hours, he will have a blood alcohol concentration of 0.04. After three hours, his blood alcohol concentration will be down to 0.03, after four hours, it will be down to 0.01, and only after five hours will he have a blood alcohol concentration of 0.00.
• At 150 pounds, a man will have a blood alcohol concentration of 0.05 after two drinks. If he drinks them over one hour, he will have a blood alcohol concentration of 0.04, and after two hours, he will have a blood alcohol concentration of 0.02. After three hours, his blood alcohol concentration will be down to 0.003, and after four hours, it will be down to 0.00.
• At 200 pounds, a man will have a blood alcohol concentration of 0.04 after two drinks. If he drinks them over one hour, he will have a blood alcohol concentration of 0.004, and after two hours, he will have a blood alcohol concentration of 0.00.

After Three Drinks

Three American standard drinks will produce, on average, a blood alcohol concentration of about 0.06. At this point, the negative effects of alcohol start to show.

Once the typical man has had three drinks, judgment will be impaired, often affecting the ability to make rational decisions, particularly around risk-taking activities such as driving or sex. Perception, memory, coordination, alertness, and self-control will also be impaired.

After a man has three standard drinks, the equation changes even further:

• At 100 pounds, a man will have a BAC of 0.11. If he drinks them over one hour, he will have a BAC of 0.10, and if he drinks them over two hours, he will have a BAC of 0.08. After three hours, his BAC will still be at 0.07, and after four hours, it will be at 0.05. After five hours, it will be down to 0.03, after six hours, it will be at 0.02, and after six hours, it will be at 0.001. Only after a whopping seven hours will he have a BAC of 0.00.
• At 150 pounds, a man will have a BAC of 0.08. If he drinks them over one hour, he will have a BAC of 0.06, and after two hours, he will have a BAC of 0.04. After three hours, his BAC will be down to 0.03, and after four hours, it will be down to 0.01. By five hours, it will be down to 0.00.
• At 200 pounds, am will have a BAC of 0.06. If he drinks them over one hour, he will have a BAC of 0.004, and after two hours, he will have a BAC of 0.02. After three hours, his BAC will be down to 0.01, and after four hours, it will be down to 0.00.

After Six Drinks

The effects noted at the three drink level (or a BAC of 0.06) will become more pronounced with each additional drink. Six drinks will produce a BAC of about 0.12 unless the alcohol consumed over a long period of time.

The speed by which a man would reach this level would vary:

• At 100 pounds, a man would reach a BAC of 0.12 by drinking three drinks in less than one hour or four drinks over two hours.
• At 150 pounds, a man would reach this level by consuming six drinks over two to three hours.
• At 200 pounds, a man would reach this level if he drank six drinks in less than one hour. If these people drank more slowly, it might take eight or nine drinks to reach this level over two or three hours.

More Than Six Drinks

After six drinks, the BAC and symptoms of severe intoxication and poisoning rapidly increase:

• After seven to eight drinks, your BAC will have reached 0.15 (or the equivalent of half a pint of whiskey). Most people have difficulty walking in a straight line at this point.
• After 10 drinks, your BAC will have reach 0.2. By this stage, most people will blackout and have no little or memory of what happened. In younger people, this level can be fatal.
• After 15 drinks, the BAC will have reached 0.3. Unconsciousness is all but inevitable.
• After 20 drinks, the BAC will have reached 0.45, a dose considered fatal for adults. Death usually occurs as a result of cardiac or respiratory arrest.

A Word From Verywell

In general, three drinks or more will produce negative effects. These negative effects will increase the more you drink and the more quickly you drink. Because you feel "up" and emboldened, you may not even be aware of how badly you are impaired. These effects can be particularly pronounced in smaller men.

If you are driving, the evidence is clear that you are safer not drinking at all. Research also shows that the severity of life-threatening motor vehicle accidents increases significantly at BACs far lower than the current U.S. limit of 0.08.

It is also worth noting that the majority of sexual assaults occur when one or both people have been drinking. So having more than three drinks at a bar, club, or party may leave you vulnerable to impropriate and harmful behaviors.