What Is Blood Alcohol Concentration (BAC)?
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Blood Alcohol Concentration (BAC) refers to the percent of alcohol (ethyl alcohol or ethanol) in a person's blood stream. A BAC of .10% means that an individual's blood supply contains one part alcohol for every 1000 parts blood.
Factors That Impact BAC
- Number of standard drinks
- Amount of time in which drinks are consumed
- Body weight
- Water composition
- Enzyme production and levels
- Sex assigned at birth and corresponding hormone levels
- Medications
- Food
For more information about alcohol metabolism, check out our alcohol metabolism page.
Standard Drink
One Standard Drink
- One 12 oz. regular beer (4.5-6% alcohol)
- One 12oz. White Claw (5% alcohol)
- One 7 oz. malt liquor (7% alcohol)
- One 5 oz. glass of wine (12% alcohol)
- One 1.5 oz. shot of hard liquor (40% alcohol)
- One-third jigger (.5 oz.) of Everclear (95% alcohol)
More Than One Standard Drink
- One 16 oz. cup of beer = 1.4 drinks
- One 40 oz. beer = 3.6 drinks
- One 22 oz. malt liquor = 3 drinks
- One 12 oz. glass of wine = 2.9 drinks
- One 12 oz. margarita = 2–4 drinks, depending on ingredients
- One 12 oz. cup of trashcan punch = 4–10 drinks, depending on ingredients
Effects of Alcohol at Various Blood Alcohol Concentration Levels
BAC | Physical and Mental Effects |
---|---|
.01 - .03 | No apparent effects. Slight mood elevation. In California, you will test as legally impaired at .01% BAC if you are under 21. It is illegal to drive or bike at this level. |
.04 - .06 | Feeling of relaxation. Sensation of warmth. Minor impairment of reasoning and memory. |
.07 - .09 | Mild impairment of balance, speech, vision and control. In California, you will test as legally impaired at .08% BAC if you are over 21. It is illegal to drive or bike at this level. |
.10 - .12 | Significant impairment of motor coordination and loss of judgment. Speech may be slurred. |
.13 - .15 | Gross impairment of motor control. Blurred vision and major loss of balance. Onset of dysphoria (anxiety, restlessness). |
.16 - .20 | Dysphoria predominates. Nausea may appear. Drinker has the appearance of “sloppy drunk.” |
.25 - .30 | Severe intoxication. Needs assistance walking. Mental confusion. Dysphoria with nausea and some vomiting. |
.35 - .40 | Loss of consciousness. Brink of coma. |
.40 and up | Onset of coma. Likelihood of death due to respiratory failure. |