Quick answer: In most of the United States, the legal blood alcohol limit for driving is 0.08% BAC for drivers age 21 and older. Some places use lower limits, such as 0.05% in Utah, and commercial or underage drivers often face stricter rules.

What BAC means

BAC stands for blood alcohol concentration or blood alcohol content. It measures how much alcohol is in your blood, and even below the legal limit, alcohol can still impair driving ability.

Common legal limits

  • 0.08% BAC : standard legal driving limit in most U.S. states for adults 21+.
  • 0.05% BAC : lower legal limit in some places, including Utah.
  • Zero-tolerance or lower thresholds may apply for underage drivers or certain professional drivers, depending on local law.

Important note

A BAC limit is a legal threshold, not a “safe to drive” line. Impairment can begin before 0.08%, and risk rises as BAC increases.

If you want, I can also give you the limit for your country or state.