Levels of Being Drunk What Every BAC Level Does to Your Brain

Alcohol switches your brain off in a set order, and the last switch is the one that keeps you breathing. This list climbs the nine levels of being drunk, from a blood alcohol level of 0.02 up to 0.40 and beyond, then tackles the sobering-up myths and the morning after. The numbers are averages, since your weight, sex, food and how fast you drink all move them. Read it as an explainer of what alcohol does, not a challenge or a guide.

Level 1: the warm glow at 0.02

A drink or two in, you feel like there's a warm blanket around you. The warmth is a lie. Blood rushes to your skin while your core actually cools down.

BAC, or blood alcohol concentration, is grams of alcohol per 100 ml of blood, so 0.02 doesn't mean you're 2% beer.

The first thing to clock out is judgement, up in your frontal cortex. You also get worse at doing two things at once, so walking and texting becomes a group project. In Sweden, Norway and Poland, 0.02 is already the driving limit. You feel completely sober, which is exactly what someone at 0.02 would say.

Level 2: tipsy at 0.05

Inhibitions are down, and karaoke has gone from a threat to a plan. Everyone seems louder, too. Spoiler, it's you. Alcohol dulls your hearing a little, which might be why.

Your attention shrinks to whatever is right in front of you, and consequences stop getting a look in. You also feel better looking. In one study, men who only thought they'd been drinking rated themselves as more attractive, while the judges saw no difference at all. 0.05 is the driving limit in Utah and in most of Europe.

Level 3: legally drunk at 0.08

For a 160-lb man, this is about four drinks in an hour, and for a 120-lb woman about three in two hours. 0.08 is the driving limit in every US state except Utah, and it's also the official definition of a binge.

Down in the cerebellum, coordination starts to slip, so your balance, vision and reaction time all get worse. Saying "I'm fine to drive" at 0.08 is like marking your own homework. Your risk of a fatal crash is six to ten times higher than when sober, depending on your age. In 2023, drink-driving crashes killed 12,429 people in the US, which is one every 42 minutes. For how a sleepless night compares with these numbers, see the 7 levels of sleep deprivation.

Over the limit, your keys go to someone sober and you get a lift home.

Level 4: sloppy at 0.10 to 0.12

Speech slurs and thinking slows, so a word like "statistically" comes out as a sneeze in three acts. Your walk gets wobbly, and even your eyes start to jitter.

Here's the twist. The fun has already peaked. From this point the high fades and anxiety moves in, just as texting your ex starts to feel like a sensible idea. Later on you'll even feel more sober than you are, which is called the Mellanby effect. Your feelings are a satnav announcing you've arrived while you're parked in a pond.

Level 5: wasted at 0.15

You're negotiating with gravity now, and gravity is winning. Balance is mostly gone and the room is spinning, although the room is fine and it's you. That rumble is your brainstem, which has an actual vomiting centre, pulling the fire alarm.

This is nearly twice the legal limit. In 2024, 21% of US drivers killed in crashes were at this level or higher. Your liver needs about ten hours to clear this much, so if you stop drinking at midnight, you won't be sober until around 10am.

Level 6: blackout at 0.20

Your eyes are still filming, but nothing is being saved. The hippocampus, the part of the brain that files your night into long-term memory, has clocked off. You aren't passed out. You can be awake, talking, walking and even driving, and you won't remember any of it. Blackouts can start from about 0.16, especially if you drink fast or on an empty stomach.

In one survey, 51% of students who'd ever had a drink had blacked out at least once. In another study, about half said their next memory was waking up the following morning, often somewhere unfamiliar. Some students found out afterwards that they'd driven, damaged property or had unprotected sex during a blackout. Even one blackout is a reason for concern.

Level 7: stupor at 0.25 to 0.30

The brain is in power-saving mode. Very little gets through, and you can pass out without warning. This is overdose territory, with confusion, stupor, trouble staying awake and vomiting.

Here's something almost nobody knows. BAC can keep rising after the last drink, even after someone has passed out, because alcohol still in the stomach keeps getting into the bloodstream. That makes "let them sleep it off" dangerous. Their gag reflex can switch off and they could choke. If your friend is on this level, you've just been promoted to designated adult.

Level 8: coma risk at 0.35

By now the only part of the brain still properly lit is the brainstem, which runs your breathing and heartbeat. In an overdose, even that starts shutting down. People who rarely drink often go unconscious at this level. It's no longer a big night out. It's a hospital night.

Watch for fewer than eight breaths a minute, ten seconds or more between breaths, pale or bluish skin, or someone you can't wake. A high tolerance won't protect anyone here. Even seasoned drinkers can die when their breathing slows.

Level 9: lethal at 0.40 and up

This is five times the legal limit and potentially fatal. Breathing can slow until it stops, and even survivors can be left with permanent brain damage. A CDC study found that about six Americans a day died of alcohol poisoning, and three in four of them were adults aged 35 to 64.

At this level, the hero is the friend who calls for help. If someone can't wake up or is breathing slowly, call 911, or your local emergency number, straight away, and don't wait for every sign. Never leave them alone. If they're lying down, roll them onto their side so they don't choke. Coffee and cold showers won't fix an overdose.

Sobering-up myths

Your liver clears about 0.015 an hour, and nothing you do changes that. Coffee doesn't sober you up. It makes a wide-awake drunk with the same BAC and more opinions. A cold shower makes a cold, wet drunk, and walking it off just moves the drunk somewhere else. The 2am kebab can't mop up alcohol that's already in your blood either. It's a kebab, not a sponge.

Water and sleep won't speed things up. Getting from 0.08 back to zero takes over five hours, and only time works. Feeling sober isn't the same as being sober.

The morning after

The cruel part is that a hangover peaks when your BAC hits about zero. You're finally sober, and you feel your worst. The warm glow from level one has sent its invoice.

Alcohol suppresses vasopressin, the hormone that tells your body to hold on to water. So you pee like a leaky tap and wake up feeling like a raisin. Your sleep was broken, too, and that morning dread is a mini withdrawal. Hangxiety is real.

And "beer before liquor"? In a study of 90 volunteers, the order made no difference. It's the amount that counts. Hair of the dog is just hitting snooze on a fire alarm. The only real cure is time.

The short version

• Alcohol switches the brain off in order, starting with judgement and ending with the brainstem that keeps you breathing.
• Blackouts can start from about 0.16, and BAC can keep rising after someone passes out.
• If someone can't be woken or is breathing slowly, call for help straight away, stay with them and roll them onto their side.
• Only time sobers you up, at about 0.015 an hour. Coffee, cold showers and kebabs don't.