In the United States, a blood alcohol concentration (BAC) of 0.08% is the legal threshold for drunk driving in 49 states. Utah sets its limit lower at 0.05%. But “drunk” in the physical sense doesn’t map neatly to a single number. Impairment starts well before 0.08%, and the BAC at which you feel noticeably drunk depends on your body weight, sex, how much you’ve eaten, and how fast you’re drinking.
The Legal Line: 0.08% in Most States
Every state except Utah defines legal intoxication for drivers as a BAC of 0.08%. At that level, you have reduced muscle coordination, impaired judgment and reasoning, and a harder time detecting danger. Utah lowered its limit to 0.05% in December 2018, becoming the first state to do so. After the change, traffic deaths in Utah dropped from 281 fatalities in 2016 to 248 in 2019, even as total miles driven increased.
For drivers under 21, the threshold is far stricter. All states set the limit at 0.02% or lower, which essentially means any detectable amount of alcohol.
What Each BAC Level Actually Feels Like
Legal limits aside, alcohol affects your brain and body on a sliding scale. Here’s what to expect at each stage:
- 0.02%: A single drink for most people. You may notice a slightly altered mood, mild relaxation, and a subtle shift in judgment. Most people wouldn’t describe this as “drunk.”
- 0.05%: You feel loosened up. Alertness drops, inhibitions lower, and judgment is clearly impaired, even if you feel fine. This is the level Utah considers legally drunk for driving.
- 0.08%: The legal limit in most states. Muscle coordination is noticeably reduced, and your ability to reason through decisions or spot hazards declines significantly.
- 0.10% to 0.15%: Slurred speech, poor balance, and impaired memory. At the higher end, nausea and vomiting are common. Most people would describe themselves as clearly drunk in this range.
- 0.16% to 0.30%: Difficulty walking and speaking. Confusion, drowsiness, and memory blackouts become likely. Vomiting and loss of consciousness can occur.
- 0.30% to 0.40%: This is alcohol poisoning territory. Loss of consciousness is likely, and the risk of death rises sharply.
- Above 0.40%: Potentially fatal. Coma and respiratory arrest (your body stops breathing) become real possibilities.
The gap between “feeling a buzz” and “dangerously drunk” is smaller than most people think. Someone at 0.15% is roughly twice the legal driving limit but may have gotten there with just a few drinks over a short period.
Why the Same Number of Drinks Hits People Differently
Two people can drink the same amount and reach very different BAC levels. Body weight is the most obvious factor: a larger body has more blood volume to dilute the alcohol. But biological sex plays a surprisingly specific role beyond just size differences. Men produce a stomach enzyme that breaks down about 30% of alcohol before it ever reaches the bloodstream. Women carry the gene for this enzyme, but it’s switched off, meaning more alcohol passes directly into their blood from every drink. This is one reason women typically reach higher BAC levels than men of similar weight drinking the same amount.
Food in your stomach also matters. Eating before or while drinking slows the rate at which alcohol enters your small intestine, where most absorption happens. Drinking on an empty stomach can cause your BAC to spike faster and peak higher. The type of drink matters less than you’d think, since what counts is total alcohol consumed, but carbonated mixers can speed absorption slightly.
How Long It Takes BAC to Drop
Your liver processes alcohol at a fairly fixed rate: roughly 0.015 to 0.020 percentage points per hour. That means if you’re at 0.08%, it takes four to five hours to reach 0.00%. Coffee, water, food, and cold showers don’t speed this up. They might make you feel more alert, but your BAC drops at the same steady pace regardless.
This is where people often misjudge their sobriety. If you stop drinking at midnight with a BAC of 0.12%, you could still be above the legal limit at 3 or 4 a.m. A night of heavy drinking that pushes you to 0.20% could mean you’re still impaired well into the next morning.
What Counts as One Drink
A standard drink in the U.S. contains 0.6 ounces (14 grams) of pure alcohol. That translates to 12 ounces of regular beer at 5% alcohol, 5 ounces of wine at 12%, or 1.5 ounces (one shot) of 80-proof liquor at 40%. Many real-world servings exceed these amounts. A pint of craft beer at 7% alcohol is nearly two standard drinks. A generous wine pour at a restaurant can easily be 7 or 8 ounces. If you’re estimating your BAC based on “number of drinks,” undersized mental math is one of the most common mistakes.
For a rough estimate, one standard drink raises the average person’s BAC by about 0.02 to 0.03 percentage points. A 160-pound man drinking four beers in two hours might land around 0.08%. A 130-pound woman drinking the same amount in the same timeframe would likely be well above that. These are approximations, not guarantees, and individual variation is wide enough that personal breathalyzer readings are the only reliable way to know your actual number.