what blood alcohol level is drunk
A blood alcohol concentration (BAC) of about 0.08% is commonly considered “legally drunk” for driving in the U.S., while noticeable intoxication can start at lower levels like 0.02%–0.05%. Effects become more severe as BAC rises, with 0.15% and above often causing major impairment, and 0.30%–0.40% being dangerous or life-threatening.
BAC ranges
| BAC | Typical effects |
|---|---|
| 0.02% | Relaxation, slight loss of judgment |
| 0.05% | Lowered alertness, impaired judgment |
| 0.08% | Common legal driving limit in the U.S.; significant impairment |
| 0.15% | Vomiting, loss of balance, reduced muscle control |
| 0.30%–0.40% | Alcohol poisoning, unconsciousness risk |
Important note
“Drunk” is not a single universal medical cutoff, because people feel impaired at different BAC levels depending on body size, sex, food intake, drinking speed, tolerance, and medications. A person can be unsafe to drive well below 0.08%.
Safety
If someone has confusion, repeated vomiting, trouble staying awake, slow or irregular breathing, or can’t be awakened, treat it as a medical emergency.
TL;DR: about 0.08% BAC is the usual legal “drunk” limit for driving, but impairment can begin much earlier.
