BAC guide
BAC Chart: Blood Alcohol Levels, Effects, and Risks
Compare commonly observed effects at different BAC ranges and understand why a BAC chart cannot determine whether someone can drive.
Use the BAC CalculatorBAC ranges and commonly observed effects
This table summarizes commonly observed effects reported by NHTSA. Effects vary, and driving skills may decline before obvious intoxication.
| BAC | Common effects | Driving-related risk |
|---|---|---|
| 0.02% | Some loss of judgment and altered mood | Reduced visual tracking and divided attention |
| 0.05% | Lower alertness and coordination | Reduced steering and emergency response |
| 0.08% | Impaired reasoning, memory and reaction time | Reduced concentration and hazard perception |
| 0.10% | Clear deterioration of reaction and control | Reduced lane control and braking |
| 0.15% | Major loss of balance and muscle control | Severe impairment of control and attention |
Why the same BAC affects people differently
Drinking pattern, tolerance, medicines, food, fatigue, health and biology change how impairment appears. Tolerance may hide signs without restoring driving skills.
BAC charts and legal limits
A chart is not a legal test. Limits, units and special-driver rules differ by jurisdiction, and an offence may exist below a numerical limit. Check the official source in the country guide.