BAC Limits Table
| Driver category | Legal BAC limit | Notes |
|---|---|---|
| 21+, passenger vehicle | 0.08 (all 50 states) - Utah 0.05 | Per-se: the test alone proves DUI; impairment charges exist below it |
| Commercial driver (CDL) | 0.04 (every state) | Applies in the commercial vehicle - and most states, any vehicle |
| Under 21 | 0.00-0.02 zero tolerance | Any measurable alcohol can pull the license; threshold varies by state |
| Open container | Illegal in passenger area, all states | Driver is responsible even for a passenger's can |
| Metabolism fact | The number |
|---|---|
| Elimination rate | About 0.015 BAC per hour - one standard drink's worth |
| Standard drink (US) | 14 g pure alcohol = 12 oz 5% beer = 5 oz 12% wine = 1.5 oz 40% spirits |
| Coffee, showers, exercise, food after | Zero effect on blood alcohol - only time moves the number |
| Morning-after window | Sleep ends the hangover, not the BAC; next-day arrests are routine |
The number every US driver carries around - 0.08 - is not a safety threshold; it is a legal one, and its origin is fiscal: the 2000 federal transportation act tied highway funds to states adopting a 0.08 per-se limit, and by 2004 all fifty states had complied. Utah broke ranks in 2018 at 0.05, and the trend conversation continues in other legislatures - but today the table below is the complete map of what the law counts as driving under the influence, category by category.
Bottom line: 0.08 BAC is the per-se DUI line for drivers 21 and over in every state; Utah enforces 0.05; commercial drivers (CDL) are held to 0.04 in every state; and drivers under 21 face zero-tolerance limits between 0.00 and 0.02 depending on the state. Open containers in the passenger area are illegal everywhere. And none of these numbers mark where impairment begins - driving skills degrade from the first drink.
The honest part: BAC varies with weight, sex, drinking pace, food, and metabolism far more than people expect, and no chart can read your body - which is why the only number that is safe to drive on is zero. The table is for knowing the law's lines, not for plotting how close to them you can get.
How to use
- Find your row: age and license class set your limit - 0.08 standard, 0.05 Utah, 0.04 CDL, zero tolerance under 21.
- Treat the limit as a ceiling, not a target: impairment tests (field sobriety, drug recognition) can convict below the per-se number.
- Plan the ride home before the first drink - the metabolism facts below are why coffee, showers, and fresh air change nothing but time.
Frequently asked questions
What is the legal BAC limit in the United States?
For drivers 21 and older, 0.08 grams of alcohol per deciliter of blood is the per-se limit in all 50 states, DC, and Puerto Rico - per-se meaning no other proof of impairment is needed once the test reads 0.08. Utah is the single exception, enforcing 0.05 since December 2018. Commercial drivers are held to 0.04 nationwide, and under-21 drivers face zero-tolerance limits of 0.00 to 0.02 by state.
Why is Utah's limit 0.05 and will other states follow?
Utah's legislature passed 0.05 in 2017 (effective 2018), taking up the recommendation the National Transportation Safety Board has pushed for all states since 2013 - research shows crash risk rises measurably already near 0.05. Early data showed Utah DUI arrests fell and highway deaths dropped; several states have introduced 0.05 bills since, none has passed yet. If you drive across state lines, the limit that matters is the one where the steering wheel is.
Can I be arrested for DUI with a BAC under 0.08?
Yes. The per-se number is one path to conviction, not the only one - an officer who observes impaired driving can pursue a DUI on impairment evidence alone (dashcam driving, field sobriety tests, officer testimony) at any BAC, and some states file at 0.05-0.07 as 'impaired driving' charges. The reverse is also true: the per-se line means the state needs no impairment proof at 0.08+. There is no BAC number that certifies safe driving.
How fast does the body eliminate alcohol?
On the order of 0.015 BAC per hour - roughly one standard drink's worth - with real-world spread by body size, sex, food, and liver differences. Coffee, cold showers, exercise, and food after the fact change nothing about your blood level; time is the only thing that does. This is why 'morning after' arrests are real: the sleep that ends a hangover does not end a BAC, and drivers have been arrested well into the next day.
What happens if I refuse a breathalyzer test?
Every state's implied-consent law treats your license as consent to testing as a condition of driving: refusal triggers automatic license suspension (often longer than a first-DUI suspension), and most states allow refusal itself to be used against you in court. Some states can draw blood under warrant. Refusing does not make the case go away - it typically adds an administrative penalty on top.
What counts as one standard drink in the US?
14 grams of pure alcohol: a 12-ounce beer at about 5%, a 5-ounce glass of wine at about 12%, or a 1.5-ounce shot of spirits at 40% - all the same alcohol load. Craft beers at 8-10% and generous wine pours routinely carry the alcohol of two standard drinks, which is how 'just two beers' becomes a BAC the drinker never modeled. Counting drinks only works if the drinks are standard.