BAC Limits You Need to Know
BAC (Blood Alcohol Concentration) measures how much alcohol is in your blood. Every state has legal limits for driving.
Standard BAC Limits (All States)
Adults (21 and older): 0.08% in 49 states. Utah is the exception at 0.05%.
Under 21 (Zero Tolerance): Any detectable alcohol is illegal in every state. Most states set the limit at 0.00% or 0.02%.
Commercial drivers: 0.04% in all states when operating a commercial vehicle.
What Does 0.08% BAC Mean?
A BAC of 0.08% means there are 0.08 grams of alcohol per 100 milliliters of blood. For most people, this is roughly:
But many factors affect BAC: body weight, food consumed, medications, and how quickly you drink.
Important: Impairment Starts Below 0.08%
Even at 0.02% BAC, your ability to divide attention between tasks is reduced. At 0.05%, your coordination and ability to track moving objects are impaired. You can be charged with impaired driving even below 0.08% if an officer determines you are unsafe to drive.
Utah's Lower Limit
Utah lowered its BAC limit to 0.05% in 2018. This means one drink could put you over the legal limit.
Implied Consent Law
Every state has an implied consent law. This means by driving on public roads, you automatically agree to submit to a BAC test if an officer suspects DUI. Refusing the test results in automatic license suspension — even if you are not actually over the limit.
DUI Penalties
Penalties for DUI/DWI vary by state but typically include:
The Only Safe Amount
The only guaranteed way to avoid a DUI is to not drink and drive at all. If you drink, use a rideshare, taxi, or designated driver.
Practice BAC Questions
Take a free practice test with alcohol and DUI questions for your state.