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Amount of Alcohol Consumed
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This calculator uses the standard version of the Widmark formula to produce the BAC estimate.
A common version is: BAC = [Alcohol (g) / (Body weight (g) x r)] x 100
- Alcohol (g): The mass of pure alcohol consumed.
- Body weight (g): The person's weight.
- r: The Widmark factor, a gender-specific constant for body water (typically 0.68 for males and 0.55 for females).
To account for alcohol elimination over time, a rate (β) is subtracted:
BAC = [Alcohol (g) / (Body weight (g) x r)] x 100 – (Hours x β)
- Hours: Time passed since drinking started.
- β (beta): The elimination rate, averaging 0.015% per hour.
Effects by Blood Alcohol Concentration
Below are the effects of different levels of Blood Alcohol Concentration, based on the guidelines of the USA's National Highway Traffic Safety Administration.
| BAC % | Behavior | Impairment |
|---|---|---|
| 0.001–0.029 | Mild relaxation, otherwise normal. | Subtle; minor loss of coordination. |
| 0.030–0.059 | Mild euphoria, lowered inhibitions. | Reduced alertness and judgment. |
| 0.060–0.099 | Buzzed, over-confident, exaggerated emotions. | Impaired reasoning, vision, and reaction time. |
| 0.100–0.199 | Drunk, boisterous, or sloppy. | Major motor impairment; slurred speech. |
| 0.200–0.299 | Dazed, confused; blackouts likely. | Needs help walking. Nausea/vomiting. |
| 0.300–0.399 | Stupor; likely loss of consciousness. | Critical; little comprehension. Bladder control lost. |
| 0.400–0.500 | Coma; unconscious. | Life-threatening; breathing and heart rate suppressed. |
| >0.50 | Unconscious. | Potentially fatal; high risk of complete respiratory failure. |
DISCLAIMER: The BAC calculator is meant for educational purposes only. As per the guidelines of the Center for Disease Control, alcohol is a substance that can severely impact your health, so exercise caution. The BAC calculator and information generated from it is not intended to replace the medical advice of your doctor or health care provider and should not be relied upon; nor do the BAC calculator or information generated from it constitute legal advice. Please consult your healthcare provider for advice about a specific medical condition and legal counsel for any legal questions. There is no blood alcohol calculator that is 100% accurate because of the numerous factors and complexities relating to alcohol consumption by of different individuals. In addition to the gender, body weight and amount of alcohol consumed in a time period, blood alcohol content of any individual person is influenced by that person’s metabolism, health issues, medications taken, history of alcohol consumption and the amount of food and non-alcoholic beverages eaten before or during alcohol consumption, among other factors. The best that can be done is a rough estimation of the BAC level based on known inputs.
Our medical reviewers have verified the educational content and confirmed that the calculator correctly implements the standard BAC estimation algorithms. Note that individual results vary significantly. This is an educational estimate only.