Blood Alcohol Concentration (BAC) Calculator
Blood Alcohol Concentration (BAC) Calculator
Blood alcohol concentration (BAC) is a standard way of measuring the level of alcohol in a person’s system, commonly associated with intoxication. It is expressed as the percentage of alcohol present in the blood. For instance, in the United States, a BAC of 0.08% means there are 0.08 grams of alcohol for every 100 milliliters of blood.
In the U.S., the legal driving limit for individuals aged 21 and over is 0.08% BAC. Anyone at or above this level may face legal consequences. For drivers under 21, restrictions are much stricter, with most states setting the legal limit between 0.01% and 0.05%.
Alcohol and Its Health Effects
Alcohol affects the body in both the short and long term. Immediate effects include intoxication, dehydration, and impaired judgment, while prolonged consumption may lead to liver and brain damage, changes in metabolism, or the development of alcohol dependence.
Some research has suggested that limited alcohol consumption, such as a daily glass of red wine, may have certain health benefits. However, these findings are not universally accepted, and any possible benefits come with potential risks.
Light to Moderate Drinking
Defined as about one drink per day (12 oz beer, 5 oz wine, or 1.5 oz distilled spirits), light to moderate alcohol use may be linked to:
- A lower risk of heart disease
- Reduced risk of ischemic stroke
- Slightly lower chance of developing diabetes
Still, even small amounts of alcohol can increase the risk of certain cancers, and drinking should never be used as a “health strategy.”
Heavy Drinking
According to the Mayo Clinic:
- For women and men over 65: more than 3 drinks per day is considered heavy drinking.
- For men under 65: more than 4 drinks per day, or 14 drinks per week, is heavy drinking.
Chronic heavy alcohol use can cause:
- Higher risk of several cancers
- Sudden death in people with heart disease
- Damage to the heart muscle (leading to heart failure)
- Stroke and high blood pressure
- Liver disease
- Brain damage
- Accidental injury or death
The bottom line: no one should begin drinking for health benefits, and those who already drink moderately should consult a doctor to ensure it is safe for them.
BAC and Levels of Impairment
The impact of alcohol depends on how much is present in the blood. The table below shows typical effects by BAC range:
| BAC (%) | Behavior | Impairments |
| 0.001–0.029 | Person appears normal | Only detectable with special tests |
| 0.030–0.059 | Mild euphoria, relaxation, talkativeness, lowered inhibitions | Reduced focus |
| 0.060–0.099 | Blunted emotions, decreased pain sensitivity, disinhibition, outgoing behavior | Impaired reasoning, vision, depth perception |
| 0.100–0.199 | Loudness, poor coordination, nausea, slurred speech, possible vomiting | Slowed reflexes, poor motor control, erectile dysfunction |
| 0.200–0.299 | Emotional instability, nausea, partial loss of awareness, stupor possible | Severe motor impairment, memory blackouts, unconsciousness |
| 0.300–0.399 | Stupor, CNS depression, slipping in and out of consciousness | Impaired breathing, balance, heart rate, bladder function |
| 0.400–0.500 | Severe CNS depression, coma risk | Dangerously impaired heart and lung function |
| >0.50 | – | High likelihood of death |