The legal limit for drinking is the alcohol level above which an individual is subject to legal penalties (e.g., arrest or loss of a driver's license).

• Legal limits are measured using either a blood alcohol test or a breathalyzer.
• Legal limits are typically defined by state law, and may vary based on individual characteristics, such as age and occupation.

All states in the United States and almost all in the world have adopted 0.08% (80 mg/dL) as the legal limit for operating a motor vehicle for drivers aged 21 years or older. However, drivers younger than 21 are not allowed to operate a motor vehicle with any level of alcohol in their system.
Note: Legal limits do not define a level below which it is safe to operate a vehicle or engage in some other activity. Impairment due to alcohol use begins to occur at levels well below the legal limit.