What Happens at Various Levels of Blood Alcohol Content (BAC)?

Compiled by Jon Weeldreyer, MA, CAAC

Blood alcohol content is usually expressed as a percentage of alcohol (generally in the sense of ethanol) in the blood. For instance, a BAC of 0.10 means that 0.10% (one tenth of one percent) of a person's blood, by volume is alcohol.

.02 - .04

People begin to feel relaxed, happy, and have lowered inhibitions

.04 - .08

Impairment begins: poor coordination, reflexes, and muscle control; loss of self-control and driving capability

.08 - .10

All states impose penalties for driving with a BAC greater than 0.08 for adult drivers 21 years old and older. However there are lower limits for commercial operators (0.04) and zero tolerance for drivers under 21 years of age.

.10 - .15

Loss of balance, impaired movement and slightly slurred speech

.15 - .25

Slurred speech, staggering, confusion, loss of perception (color and depth), vision problems, double vision

.25 - .40

Most people are in a stupor and barely conscious; some may die

.40 - .50+

Most people are unconscious; respiratory and pulmonary system at high risk of shut down. Death is likely

Note: Many factors influence how many drinks it takes to reach a particular BAC, including age, gender, rate of consumption, drink strength, body type, fat/muscle content, metabolism, hydration, emotional state, medication you are taking, food you’ve consumed, carbonation of drinks, alcohol tolerance and overall health.