Blood Alcohol Concentration (BAC) Calculator
Estimate your Blood Alcohol Concentration based on your weight, gender, drinks consumed, and time elapsed. Understand your level of impairment and legal limits.
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What is Blood Alcohol Concentration (BAC)?
Blood alcohol concentration (BAC) is a commonly used measure of alcohol intoxication, also known as drunkenness. It is typically expressed as a percentage of alcohol per volume of blood. For example, in the United States (US), a BAC of 0.08 (0.08%) would translate to 0.08 grams of alcohol per 100 mL of blood.
In the US, the legal limit for BAC when driving is 0.08%. Drivers who are over the age of 21 (the legal drinking age in the US), who have a BAC equal to or greater than 0.08%, can face penalties. Penalties for those under the age of 21 are stricter, but vary by state. For those under the age of 21, the legal limit ranges from 0.01% to 0.05%.
Effects by Blood Alcohol Concentration
The degree of impairment caused by alcohol intoxication varies based on BAC. Impairments range from subtle effects that can only be detected with special tests at levels between 0.001-0.029%, to problems with concentration, reflexes, motor control, and more, including a serious possibility of death at 0.50% or more.
| BAC (%) | Behavior | Impairment |
|---|---|---|
| 0.001–0.029 | Average individual appears normal | Subtle effects that can be detected with special tests |
| 0.030–0.059 | Mild euphoria, Relaxation, Joyousness, Talkativeness, Decreased inhibition | Concentration |
| 0.060–0.099 | Blunted feelings, Reduced sensitivity to pain, Euphoria, Disinhibition, Extraversion | Reasoning, Depth perception, Peripheral vision, Glare recovery |
| 0.100–0.199 | Over-expression, Boisterousness, Possibility of nausea and vomiting | Reflexes, Reaction time, Gross motor control, Staggering, Slurred speech |
| 0.200–0.299 | Nausea, Vomiting, Emotional swings, Anger or sadness, Partial loss of understanding | Severe motor impairment, Loss of consciousness, Memory blackout |
| 0.300–0.399 | Stupor, Central nervous system depression, Loss of understanding, Lapses in and out of consciousness | Bladder function, Breathing, Dysequilibrium, Heart rate, Low possibility of death |
| 0.400–0.500 | Severe central nervous system depression, Coma | Breathing, Heart rate, Positional alcohol nystagmus, Possibility of death |
| >0.50 | High possibility of death | Death risk |
Alcohol and Health
Alcohol consumption has a number of short-term, as well as long-term effects. Short-term effects include dehydration and intoxication, while more long-term effects can include changes in the metabolism of the liver and brain. Alcohol consumption can also result in alcoholism, which is generally described as the use of alcohol that results in problems with mental or physical health.
Potential Benefits (Light to Moderate Use)
- Reducing the risk of developing and dying from heart disease
- Reducing the risk of ischemic stroke
- Reducing the risk of diabetes
Note: These are only potential benefits, and consuming any amount of alcohol may not necessarily result in these benefits.
Risks of Heavy Drinking
- Increased risk of certain cancers
- Sudden death from cardiovascular disease
- Heart muscle damage and heart failure
- Stroke and high blood pressure
- Liver disease
- Brain damage
- Accidental serious injury or death
Important: A person should not begin drinking for potential health benefits. Those who already drink light to moderate amounts, who have not experienced negative health effects, can probably continue drinking moderately as long as they are not at risk for becoming heavy drinkers. Most importantly, a person should consult their doctor regarding their alcohol consumption to determine what is safe for their particular situation.
⚠️ Important Disclaimer
This calculator provides estimates only and should not be used to determine if you are safe to drive or operate machinery. Many factors can affect BAC, including food consumption, metabolism rate, medications, and individual tolerance. Never drink and drive. If you have been drinking, arrange for a designated driver, use public transportation, or call a ride-sharing service. The only way to be certain of your BAC is through a professional breathalyzer or blood test.