Estimate your Blood Alcohol Concentration (BAC) using the Widmark formula based on physical properties, elapsed time, and various alcohol types.
Understanding Blood Alcohol Concentration (BAC)
Blood alcohol concentration (BAC) is the percentage of alcohol present in a person's bloodstream. For example, in the United States, a BAC of 0.08% represents 0.08 grams of pure ethanol per 100 mL of blood. In almost all US states, driving with a BAC equal to or exceeding 0.08% is legally defined as driving under the influence (DUI).
Effects by Blood Alcohol Concentration
| BAC Range | Behavioral Effects | Impairment Profile |
|---|---|---|
| 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/sadness, partial loss of understanding, impaired sensations | Severe motor impairment, loss of consciousness, memory blackout |
| 0.300–0.399% | Stupor, CNS depression, loss of understanding, lapses in consciousness, low possibility of death | Bladder function, breathing, dysequilibrium, heart rate |
| 0.400–0.500% | Severe central nervous system depression, coma, possibility of death | Breathing, heart rate, positional alcohol nystagmus |
| >0.50% | High possibility of death | Surgical anesthesia, cardiorespiratory collapse |
Alcohol Consumption Health Guidelines
Excessive alcohol intake carries significant acute and chronic health risks. According to clinical health guidelines:
- Light to Moderate Intake: Limits consumption to up to 1 drink per day for women, and up to 2 drinks per day for men.
- Heavy Drinking Thresholds: Exceeding 3 drinks on any single day or 7 drinks per week for women, or exceeding 4 drinks on any day or 14 drinks per week for men.
- Clinical Risks: Chronic high dosage is linked to cardiovascular disease, liver cirrhosis, hypertension, stroke, brain volume loss, and elevated risk of multiple forms of cancer.
How it Works & Formula
Blood Alcohol Content estimator (Widmark formula) where A is ounces of alcohol consumed, W is body weight, r is gender constant (0.73 for men, 0.66 for women), and H is hours since drinking started.
Practical Examples
A 180 lb male who consumed three 12oz beers (5% alcohol) over 2 hours has an estimated BAC of 0.034%.
Frequently Asked Questions
What is Blood Alcohol Concentration (BAC)?
BAC represents the percentage of alcohol in the bloodstream. A BAC of 0.08% indicates 0.08 grams of alcohol per 100 mL of blood, which is the legal limit for driving in the United States and many other countries.
What factors affect BAC?
Your weight, gender, number of drinks, the speed of consumption, food intake, and the time elapsed since your first drink all impact your BAC.
How is BAC metabolized?
On average, the human body metabolizes alcohol at a rate of roughly 0.015% BAC per hour, irrespective of body size, gender, or tolerance.