Driving after drinking poses serious risks — not just for you, but for all road users. In this guide you’ll learn the key BAC (blood alcohol concentration) limits that apply across U.S. states, how they differ for commercial and under-21 drivers, and why using a reliable BAC Calculator is a smart move. 🚗 🍷
What is a BAC limit — and why it matters
Blood Alcohol Concentration (BAC) measures how much alcohol is in your bloodstream. Even relatively low levels can impair coordination, judgment and reaction time. For most U.S. states, a BAC of 0.08% is the legal cutoff for adults to drive. [1]
Here are some key points:
-
The federal incentive required states to adopt a 0.08% “per se” limit for adult drivers (21+) — meaning if you’re at or above that level you are automatically in violation. [1]
-
Some states apply lower limits for commercial drivers (CDL), or drivers under 21 (zero-tolerance laws). [2]
-
One state, Utah, has already lowered its adult driver limit to 0.05%. [3]
Because impairment starts earlier than many realize, knowing your local limit and using a BAC chart or calculator helps avoid tragic consequences.
Adult Drivers (21+) — Per-Se BAC Limits by State
Nearly all states set the adult driver limit at 0.08% BAC. [1][2] The notable exception:
-
Utah — 0.05% for adult drivers. [3]
While exact penalty thresholds (e.g., “enhanced” penalties at 0.15% BAC) vary, the starting threshold remains largely uniform. [2]
Mini Table for Clarity:
|
Driver Category
|
Typical Limit
|
Notes
|
|
Adult driver (21+) non-commercial
|
0.08%
|
Standard in most states. [1]
|
|
Adult driver in Utah (21+)
|
0.05%
|
Only state with this lower limit. [3]
|
|
Commercial driver (CDL)
|
~0.04%
|
Many states apply lower limits. [2]
|
|
Under-21 driver
|
0.02% or less – often “zero-tolerance”
|
[4]
|
Because of these uniform heavy-lift thresholds, it’s especially important to check local state laws if you’re traveling or moving.
Commercial Drivers & Special Categories
Commercial vehicle operators, drivers on probation, or those with prior DUI/DWI offenses often face **lower BAC limits**. For example:
-
Many states set the commercial driver limit at 0.04% BAC. [2]
-
Some states impose even stricter rules for drivers with prior convictions. [4]
This reinforces that even if you feel “okay” after a drink, you may be over the limit if you’re a commercial driver or in a regulated category.
Under-21 Drivers (Zero-Tolerance Laws)
Young drivers face especially strict limits. Many states apply a “zero-tolerance” rule — meaning any measurable alcohol may lead to penalties. [4]
-
About 34 states set an under-21 BAC limit at 0.02% g/dL. [4]
-
Some states go even lower, to 0.00% (any detectable alcohol) for under-21 drivers. [4]
These rules reflect both physiology (younger drivers may react differently) and public safety goals.
Why the Variation Matters + How Impairment Starts Early
Although 0.08% is often treated as the threshold for automatic offences, research shows impairment begins well **before** that level. For example:
-
The American Automobile Association (AAA) points out that at 0.05% BAC, many drivers have measurable deficits in braking, lane-keeping and reaction. [5]
-
The National Highway Traffic Safety Administration (NHTSA) states the risk of being involved in a fatal crash increases rapidly at BACs of 0.08% and above. [1]
Hence when you use a BAC chart or our BAC Calculator, your safest bet is to plan as though any alcohol may affect you, particularly if you drive soon after.
State-by-State Snapshot (selected states)
Here are a few illustrative examples — always verify for your specific state before driving[3][5][6]:
|
State
|
Per se BAC
|
Under‑21
|
Enhanced penalty
|
|
Alabama
|
0.08%
|
0.02%
|
0.15%
|
|
Alaska
|
0.08%
|
0.00%
|
0.15%
|
|
Arizona
|
0.08%
|
0.00%
|
0.15%
|
|
Arkansas
|
0.08%
|
0.02%
|
0.15%
|
|
California
|
0.08%
|
0.02%
|
0.16%
|
|
Colorado
|
0.08% (DWAI ≥0.05%)
|
0.02%
|
0.17%
|
|
Connecticut
|
0.08%
|
0.02%
|
0.16%
|
|
Delaware
|
0.08%
|
0.02%
|
0.15%
|
|
District of Columbia
|
0.08%
|
0.00%
|
0.15%
|
|
Florida
|
0.08%
|
0.02%
|
0.15%
|
|
Georgia
|
0.08%
|
0.02%
|
0.15%
|
|
Hawaii
|
0.08%
|
0.02%
|
0.15%
|
|
Idaho
|
0.08%
|
0.02%
|
0.20%
|
|
Illinois
|
0.08%
|
0.00%
|
0.16%
|
|
Indiana
|
0.08%
|
0.02%
|
0.15%
|
|
Iowa
|
0.08%
|
0.02%
|
0.15%
|
|
Kansas
|
0.08%
|
0.02%
|
0.15%
|
|
Kentucky
|
0.08%
|
0.02%
|
0.18%
|
|
Louisiana
|
0.08%
|
0.02%
|
0.15%
|
|
Maine
|
0.08%
|
0.00%
|
0.15%
|
|
Maryland
|
0.08%
|
0.02%
|
0.15%
|
|
Massachusetts
|
0.08%
|
0.02%
|
0.20%
|
|
Michigan
|
0.08%
|
0.02%
|
0.17%
|
|
Minnesota
|
0.08%
|
0.00–0.02%
|
0.16%
|
|
Mississippi
|
0.08%
|
0.02%
|
—
|
|
Missouri
|
0.08%
|
0.02%
|
0.15%
|
|
Montana
|
0.08%
|
0.02%
|
—
|
|
Nebraska
|
0.08%
|
0.02%
|
0.15%
|
|
Nevada
|
0.08%
|
0.02%
|
0.18%
|
|
New Hampshire
|
0.08%
|
0.02%
|
0.18%
|
|
New Jersey
|
0.08%
|
0.01%
|
0.10%
|
|
New Mexico
|
0.08%
|
0.02%
|
0.16%
|
|
New York
|
0.08%
|
0.02%
|
0.18%
|
|
North Carolina
|
0.08%
|
0.00–0.02%
|
0.15%
|
|
North Dakota
|
0.08%
|
0.02%
|
0.18%
|
|
Ohio
|
0.08%
|
0.02%
|
0.17%
|
|
Oklahoma
|
0.08%
|
0.02%
|
0.17%
|
|
Oregon
|
0.08%
|
0.00–0.02%
|
—
|
|
Pennsylvania
|
0.08%
|
0.02%
|
0.16%
|
|
Rhode Island
|
0.08%
|
0.02%
|
0.15%
|
|
South Carolina
|
0.08%
|
0.02%
|
0.16%
|
|
South Dakota
|
0.08%
|
0.02%
|
0.17%
|
|
Tennessee
|
0.08%
|
0.02%
|
0.20%
|
|
Texas
|
0.08%
|
0.02%
|
0.15%
|
|
Utah
|
0.05%
|
0.02%
|
0.16%
|
|
Vermont
|
0.08%
|
0.02%
|
—
|
|
Virginia
|
0.08%
|
0.02%
|
0.15%
|
|
Washington
|
0.08%
|
0.02%
|
0.15%
|
|
West Virginia
|
0.08%
|
0.02%
|
0.15%
|
|
Wisconsin
|
0.08%
|
0.02%
|
0.15%
|
|
Wyoming
|
0.08%
|
0.02%
|
0.15%
|
These variations illustrate how important it is to check the local law if you cross state lines.
Practical Tips for Staying Safe
-
Use our free BAC Calculator to estimate your level safely.
-
Allow plenty of time for alcohol metabolism — typically ~ 1 standard drink per hour is a rough rule, though many factors (weight, food, metabolism) affect this. [8]
-
Even if you’re under the legal limit, impairment may still be present — don’t rely on “just under 0.08% = safe”.
-
If driving commercial or under 21, treat rules as stricter — aim for zero if in doubt.
-
Plan ahead: designate a sober driver, use rideshare, or stay overnight if you’ve been drinking.
Conclusion
Understanding the BAC limits in your state—and how they vary by driver category—helps you drive more safely and comply with the law. Remember: impairment begins sooner than many think, and crossing state lines can mean different rules. Use our free BAC Calculator to check your level safely, and always plan ahead if you’ll be drinking. Stay alert, stay safe, and stay within the limits.
Sources
Comparing State DUI Laws and Limits - FindLaw – https://www.findlaw.com/dui/laws-resources/comparing-state-dui-laws.html
BAC Legal Limits in Different States, Counties, & Cities - Alcohol.org – https://alcohol.org/dui/bac-limits/
Lower BAC Limits - NHTSA – https://www.nhtsa.gov/book/countermeasures-that-work/alcohol-impaired-driving/countermeasures/legislation-and-licensing/lower-bac-limits
2024 Underage BAC Limits - SAMHSA Library – https://library.samhsa.gov/sites/default/files/underage-drinking-driving-pep24-002.pdf
BAC Limit by State 2025 - World Population Review – https://worldpopulationreview.com/state-rankings/bac-limit-by-state
DUI laws in California – https://en.wikipedia.org/wiki/DUI_laws_in_California
Blood Alcohol Concentration (BAC) Limits - IARD – https://iardwebprod.azurewebsites.net/science-resources/detail/Blood-Alcohol-Concentration-%28BAC%29-Limits
Blood Alcohol Level Chart and Easy Guide - Healthline – https://www.healthline.com/health/alcohol/blood-alcohol-level-chart
Blood alcohol content level chart - Medical News Today – https://www.medicalnewstoday.com/articles/blood-alcohol-level-chart
Alcohol laws of Utah – https://en.wikipedia.org/wiki/Alcohol_laws_of_Utah