Get acquainted with how alcohol impacts your body and how to understand and calculate blood alcohol content (BAC) levels.
 

What Blood Alcohol Content Is and Why It Matters

Blood alcohol content is the percentage of alcohol in the blood. For example, a BAC of 0.10 means that 0.10% (one tenth of 1 percent) of a person's blood, breath or urine by volume is alcohol. In the U.S., having a BAC of 0.08 means you are legally intoxicated and it is illegal to drive a vehicle. If you’re going to be drinking, here are some suggestions:

• Drink responsibly. Limit the amount of alcohol you drink and alternate drinking alcohol with water or nonalcoholic beverages. Say "No" – alcohol is not for everyone, every time or every place.
• Include food. Don’t drink on an empty stomach. Food slows down the absorption of alcohol.
• Know your drink. Not all drinks are the same (a 12-ounce beer does not equal a martini).
• Plan ahead to get home safely. Designate a driver, take a cab, bus or train, stay overnight at a friend’s house or hotel, or simply walk home.
• Keep it legal. Don’t provide alcohol to anyone under 21.

Take a quick self-assessment test to look at your drinking habits and how they may affect your health.

This web-based resource provides an estimate of your blood alcohol concentration (BAC) level and the number of calories from pure ethanol. The user-friendly application is designed to raise awareness of the factors that affect the body’s metabolism of alcohol to assist individuals in responsibly consuming alcohol. BACPlus estimates the changing blood alcohol levels from the first drink until the alcohol is completely eliminated from the body. It also factors in the drinker’s sex, weight, time, and quantity of drinks being ingested.

A number of easy-to-use functionalities include:

Intuitive functionality for BAC calculating and forecasting
Convenient information on BAC/BrAC limits for over 120 countries
Automatic calorie tracking
Health information on drinking responsibly

Individuals can use the BACPlus calculator to help make good decisions.  

Please note: BACPlus is a health information tool that is meant for educational and illustrative purposes only, and should not be relied upon by you to determine how much you can drink and then drive, operate machinery, engage in sport, or work. This is because people’s bodies differ from one another in how they and their blood alcohol levels are affected by given amounts of alcohol, and this tool provides only rough estimates for an average male or female person at a given weight. IARD has endeavored to locate the correct BAC law maximums for given jurisdictions but cannot offer any assurance that they are fully correct and cannot offer legal advice as to their application. This information is also not intended to replace the medical advice of your doctor or health care provider. The best advice is to avoid harmful risks, not to violate the law, and never drink and drive.

Click here to start using BACPlus

Learn about our nutritional information, alcohol serving size and ingredients at Nutritional Information.

Although we all metabolize alcohol differently, depending on things like how much and how quickly we drink, size, gender, whether we’re drinking on an empty stomach and other personal factors, the central processes are the same for everyone.
Alcohol is metabolized in the body in three stages: absorption, distribution and elimination.

Alcohol absorption, distribution and elimination are processes that begin shortly after you take a drink. When you have a drink, it passes down the oesophagus into the stomach and into the small intestine, where the alcohol is absorbed into the blood and distributed throughout the body.
Although a small amount of alcohol is absorbed through the linings of the mouth and oesophagus, alcohol is mainly absorbed into the blood through the walls of the stomach (about 20%) and intestines (about 80%), primarily the small intestine. The absorption process happens more slowly if you have food in the stomach or intestines.
As it is absorbed, the alcohol is rapidly distributed throughout the water-containing components of the body through the bloodstream. The body's blood alcohol content (BAC) increases until it reaches a peak concentration, then gradually tapers off. Major organs, such as the liver, kidneys, lungs and brain, absorb more alcohol. Some organs, such as the brain, have special sensitivity to alcohol and its related compounds and therefore can be adversely affected.
The absorption and distribution of alcohol throughout the body happens quickly – within a few minutes of taking a drink, alcohol reaches the body's organs. Alcohol is eliminated from the body by evaporation, excretion and metabolism. On average, a healthy person eliminates about 14 grams (about 0.5 ounces) of alcohol per hour.

The liver is the body’s major organ for handling substances that get into the body.
The body can't store alcohol – it's the liver's job to break it down ('metabolize' it).
The chemical name for alcohol is ethanol. First, an enzyme in the liver breaks down the ethanol into acetaldehyde, which the body recognises as toxic. That is why another enzyme and a substance called glutathione break down the acetaldehyde into non-toxic acetic acid. This can then be broken down further into carbon dioxide and water and expelled from the body.
The liver can only metabolize a limited amount of alcohol at a time. If too much alcohol is taken into the body, the liver's store of glutathione runs out, leaving the toxic acetaldehyde to build up in the body. When this happens, the additional alcohol remains in your body tissues and bloodstream until your liver can process it. It can take three hours or more to remove the alcohol from just one drink from your system – the rate depending on factors such as your size and gender.
The more you drink, the longer it will take. There's nothing you can do to speed up the rate of metabolism.

One of the functions of the kidneys is to maintain the correct composition of the blood.
To do this, the kidneys filter your blood – all your blood will be filtered about 20 times a day. Then, useful nutrients, like protein, minerals, B vitamins, amino acids and polyphenol antioxidants are reabsorbed into the blood. Waste and excess products don't get reabsorbed – they are excreted into the urine and then eliminated from the body.
The kidneys also work to keep the volume of water in your body constant. Alcohol is a diuretic. If you drink too much, your body ends up eliminating more water than it absorbs – and as a result, you can become dehydrated, with dizziness and a headache (in other words, a hangover).

Your lungs take in air to bring oxygen to the body and get rid of waste carbon dioxide.
When the alcohol in the bloodstream reaches the lungs, some of it passes into the lungs' air sacs and then evaporates into the air. It is then exhaled and eliminated from the body.
This is the alcohol detected by breathalysers and that can be smelled on the breath.

Alcohol is a central nervous system depressant. The central nervous system includes the brain, the spinal cord and the nerves originating from the spinal cord. Intoxication occurs when alcohol acts on the central nervous system, affecting emotional and sensory function, judgment, memory and learning ability.
Different parts of the brain control different processes. Alcohol affects each of these areas of the brain at varying rates and times; as BAC increases, the effects become more pronounced.
The cerebral cortex processes information from your senses; it also controls how you think and the movement of your muscles. When alcohol affects the cerebral cortex, you take longer to process information from your senses, become less inhibited and don't think as clearly.
The limbic system is the part of the brain that controls memory and your emotions. When it is affected by alcohol, your emotions become exaggerated – for example, you could get more giddy, sad, or upset – and you start to forget things.
The cerebellum coordinates fine muscle movements, including the muscles that help you keep your balance. As alcohol affects the cerebellum, you can become shaky and uncoordinated and unsteady on your feet.

Different parts of the brain control different processes. Alcohol affects each of these areas of the brain at varying rates and times; as BAC increases, the effects become more pronounced.
The hypothalamus controls a number of functions, including sexual arousal and performance. When it is affected by alcohol, sexual arousal increases, but performance decreases. The hypothalamus also coordinates hormone production in the pituitary gland. One of these hormones is anti-diuretic hormone (ADH), which works to reabsorb water in the kidneys. Alcohol restricts production of ADH, which means the kidneys produce more urine.
The brain stem controls automatic body functions such as breathing, heart rate and consciousness. When alcohol reaches the brain stem, you become sleepy and, depending on how much alcohol you drink, you may even lose consciousness. As the concentration of alcohol in your blood increases, it may affect your heart rate, breathing and consciousness and can even lead to death.