What is BAC (Blood Alcohol Content) & Why Does It Matter? – Surely
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What is BAC (Blood Alcohol Content) & Why Does It Matter?

What is BAC (Blood Alcohol Content) & Why Does It Matter?

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Blood Alcohol Content (BAC) is used to measure alcohol in a person’s blood. It’s given as a percentage of ethanol or ethyl alcohol concentration in the bloodstream. More scientifically, it can also be measured as grams of alcohol in the blood per every 100 milliliters (mL).

It’s an important measure for legal purposes — the legal limit in most states is 0.08% — and for anyone looking to watch their BAC more closely, like the sober curious. To stay safe and healthy, you need to understand BAC, how to calculate it, and how blood alcohol content affects you.

What factors affect Blood Alcohol Content?

There are a number of factors that can affect your BAC, including some that are out of your control. These include:

  • The number of standard drinks you’ve had
  • Your rate of consumption
  • Body weight
  • Your sex and hormones
  • Your enzymes
  • Any medications or conditions you may have
  • The food you did — or didn’t — eat

Number of standard drinks

This one is simple: the more you drink, the higher your BAC will be. 

How many drinks does it take to reach a .08? It can take anywhere from 2 to 4 drinks within the hour to reach a 0.08% BAC. 

Those guidelines are based on standard drink sizes, though. Many people pour well over what’s considered the standard drink. Later in this article, we’ll list standard drink pours. Some may surprise you!

Rate Of Consumption

The faster you drink, the higher your BAC will rise. Your body needs time to absorb the alcohol. 

That means chugging your drink quickly is never a good idea. Sip your drinks, and incorporate non-alcoholic beverages in between each one.

Body Weight

Body fat matters some when it comes to BAC, but body weight is also linked to your body water content. The higher your body water content, the more efficiently your body dilutes alcohol.

Sex And Hormones

Unfortunately, women generally become intoxicated faster than men. 

Men metabolize alcohol more efficiently and have a higher body water content. They also lack the hormonal fluctuations that can make it more challenging to sober up. Some women may even find that they get intoxicated faster the week before their periods due to hormonal changes.


Higher levels of the enzyme gastric alcohol dehydrogenase found in men can be another reason why they metabolize alcohol more efficiently than women.

Medications & Conditions

Certain medications and conditions can make it more difficult for your body to metabolize alcohol. Your doctor will have the best information for you as to whether you should cut back your drinking, or even drink at all, with any pre-existing conditions.


Drinking on an empty stomach will make you feel the effects of alcohol faster. Eating a full meal before you start drinking will help your body absorb alcohol more efficiently. Keep in mind that the same doesn’t apply after you’ve been drinking, though.

Standard drinks, defined.

The number of drinks you’re consuming is an important factor in determining your BAC, but the size and strength of those drinks can matter just as much. That generous glass of wine may actually be considered two drinks.

Understanding what’s considered a standard drink could help you gauge your alcohol consumption. 

The following pours are considered standard drinks:

  • 12 ounces of beer (5% alcohol content)
  • 8 ounces of malt liquor (7% alcohol content)
  • 5 ounces of wine (12% alcohol content)
  • 1.5 ounces of a distiller spirit, like gin, rum, or vodka (40% alcohol content)

A good rule of thumb is the higher the alcohol content, the less you should drink. A beer that’s at a 5% alcohol content doesn’t include heavier varieties, for example. 

BAC Chart Of Effects

While blood alcohol concentration can vary, there are expected effects based on your BAC and body weight. One look at these effects can prove that less is always more regarding alcohol consumption.

What is the legal limit? The standard legal limit is 0.08%. A BAC at or over this number would be considered driving under the influence. Overall impairment in your thinking and movements can happen well below this number, though.

What BAC is considered drunk? A BAC of .08% is considered drunk by federal standards. Penalties can apply to drivers who reach or exceed this limit.

The average person will feel the following effects at defined BAC levels:

  • 0.02-0.04%: Most are having feelings of relaxation and slowed reaction time by this point, depending on their tolerance.
  • 0.06%: Expect more noticeable impairment and feelings of being buzzed.
  • 0.08%: This is the legal upper limit of alcohol intoxication for driving in most states. It is unsafe to drive at this level.
  • 0.10%: Expect slurred speech and worsened reaction times at this level. 
  • 0.12-0.14%: Vomiting is probable, and controlled movement is difficult.
  • 0.15-0.29%: This is the start of the danger zone for most. Blackouts are possible as you approach 0.2%. A 0.28% would then be considered a very high BAC.
  • 0.3-0.39%: Medical emergencies are possible at this level, including a loss of consciousness and alcohol poisoning.
  • 0.4% and above: Drinking can be fatal at this level.

While the highest recorded BAC fell at 1.48%, any BAC over 0.4% can cause death due to alcohol poisoning. What’s more, 

It’s crucial to be aware of how much you’ve been drinking, as well as the link between BAC and your health and safety.

How can I lower my BAC?

Just as with mythical hangover cures, there are a few common beliefs out there about ways to lower your BAC quickly. While it may be hard to hear, there’s only one surefire way to lower your blood alcohol levels: time.

Your BAC will lower as more time passes without additional alcohol. Eating a greasy burger or chugging coffee and water while intoxicated won’t sober you up faster, unfortunately.

How To Drink Safely

While there really isn’t a safe amount of alcohol if you’re planning on operating a motor vehicle, there are ways to be safer about your drinking:

  • Eat before you drink. Eating a meal before you start drinking could help you absorb any alcohol consumed faster.
  • Drink water. Keeping yourself hydrated with water could help ease any potential hangovers. It may also help to limit your drinking if you’re adding a glass of water in between alcoholic beverages.
  • Sip, don’t chug. If you’re going to indulge in alcohol, sip your drinks slowly, and moderate your drinking
  • Seek out alternatives. There are all kinds of delicious non-alcoholic beverages out there that won’t raise your BAC or that’d fit a teetotal lifestyle. Dealcoholized wine is a great place to start if you’re looking for a wine without the side effects

BAC Levels And Driving

If you’re going to drink, it’s essential to know the legal limits before that first sip and what constitutes drunk driving for law enforcement.

What is the legal alcohol limit for driving? The federal legal alcohol limit for driving in the United States is a BAC of 0.08%. For drivers under 21, that drops to anywhere from .00-.02%, to account for alcohol levels that may naturally occur.

From there, states may be more strict when it comes to driving under the influence (DUI). In Utah, for example, the legal limit is 0.05%.

If you’re pulled over and a breathalyzer shows that your BAC or breath alcohol concentration (BrAC) is well above the legal limit, enhanced penalties may apply. 

For the travelers out there, it’s important to note that some countries worldwide have zero-tolerance policies or BAC limits well below that in the United States. 

The Czech Republic, Colombia, and Vietnam all have zero-tolerance policies regarding drinking and driving, no matter your age.

A BAC of 0.08% may also look different in different people, and most states can still pull you over and charge you with a reckless driving charge even with a lower BAC. All they need to show is that your driving was reckless at the time.

Here’s our disclaimer: Your best bet is to abstain from alcohol if you’re planning on driving and opt for a delicious alcohol-free alternative instead (like us)! You could also hit a sober bar instead or make sure you have a designated driver with you.

High Blood Alcohol Over Time

A high BAC and regular alcohol use mean that you may be setting yourself up for the effects of too much drinking over time. Those have serious health effects, including:

The health benefits of abstaining from alcohol can make switching to a sober lifestyle, or just drinking less, look even more appealing. 

Even if you’ve been a heavy drinker and looking to quit, expect improved liver function, reduced cancer risk, even weight loss with a sober lifestyle.

Elevated taste, lowered risks.

You don’t need to drink at all to have a good time. The growing list of sober celebrities proves that. You don’t even need to stick to diet sodas and water while you’re out with your friends if you’re seeking a sober evening. 

Elevated nonalcoholic options like Surely’s sparkling white wine or sparkling rosé are delicious alternatives that will not only keep your BAC low, but also taste like the real thing.


  1. High blood alcohol levels in women. The role of decreased gastric alcohol dehydrogenase activity and first-pass metabolism
  2. Effects of alcohol at 0.05% blood alcohol concentration (BAC) on low speed urban driving
  3. Low Vs. High Alcohol: Central Benefits Vs. Detriments
  4. Alcohol-use disorders
  5. Alcohol and cancer
  6. Type of alcoholic beverage and incidence of overweight/obesity in a Mediterranean cohort: the SUN project

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