What is BAC?

BAC Chart

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.

In California, a person is legally intoxicated if he/she has a BAC of .08% or higher.

Factors that determine BAC

  • Number of standard drinks (see below)
  • Amount of time in which drinks are consumed
  • Body weight
  • Gender
  • Race/ethnicity
  • Medications
  • Food (to a lesser extent)

One standard drink

  • One 12 oz. regular beer (4.5% alcohol)
  • One 7 oz. malt liquor (7% alcohol)
  • One 4.5 oz. glass of wine (12% 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 trash can punch = 4–10 drinks, depending on ingredients

Effects of alcohol at various Blood Alcohol Concentration levels


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.
.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, and 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 a "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.


and up

Onset of coma. Likelihood of death due to respiratory failure.

Stanford University - Office of Alcohol Policy and Education