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Talk to friends, and you’ll find that everyone's threshold for being “wobbly” or “buzzed” from alcohol is different. That buzz is the first sign that you're getting drunk. Will five beers get you drunk, or will it be four? What factors cause the threshold to vary so widely?

Everybody Is Different

The United States has a federal blood alcohol content limit of 0.08 percent for operating motor vehicles of any kind. In some states, it's lower, and for professional drivers, it can be 0.04 percent. However, the question of whether the driver feels drunk is a whole other deal. Why can some drinkers feel sober despite being legally intoxicated, and why do others act drunk despite being legally sober?

The answer is that physiology affects alcohol’s effect on people. Age, drinking experience, fitness level, being on medical prescriptions and even genetics all impact how you process alcohol. The most common factors are:

  • Body weight: Weight is a big factor in how much alcohol is too much. A 250-pound man has a much higher consumption limit than one who is 150 pounds.

  • Metabolization: How quickly someone metabolizes food and sugar can mean processing booze better, faster or slower. There’s no way to know what your metabolization rate is. It’s something you learn from experience.

Behavioral Factors in Getting Drunk

Beyond how your body processes alcohol, there are other factors that will impact how drunk you get and how quickly. These include:

  • Food consumed: Drinking on an empty stomach gets you intoxicated quickly. Many people get tipsy off one drink on an empty stomach. You should never consume alcohol until food has been served.

  • Alcohol by volume: Every drink has a different ABV percentage. Some beer might be just 4 percent alcohol by volume, while others are as much as 8 percent. Wine tends to vary between 10.5 percent to 14.9 percent per bottle. Hard alcohol varies between 25 to 90 percent. Higher ABV gets you drunk faster.

  • Rate of consumption: Take two people and make each drink four beers of 4.5 percent ABV. If one consumes the beers at a rate of two per hour versus another drinking one beer every 75 minutes, the first will be drunk in two hours while the other is likely sober after five.

Blood Alcohol Calculator

Blood alcohol calculators are easy to find online. They’ll take what your weight is and the number of drinks you’ve had and then give you a guesstimate on what your BAC is. These calculators define a “drink” as being 1.5 ounces of hard liquor, 12 ounces of beer or 5 ounces of wine.

The problem is that alcohol calculators are frequently wrong because they assign a fixed ABV to each alcohol unit, and they don't factor in time, food consumed and so on. Saying “the drunk calculator said I was under the limit” is not a legal defense if you’re caught blowing above 0.08 percent BAC on a breathalyzer. If you're 200 pounds and enter four glasses of wine as your evening’s drinks, it'll be a 0.064 percent result on these calculators, but maybe your wine was a big, bold Bordeaux with 14.5 percent ABV and not a light 12 percent Pinot Noir, in which case you’d be legally intoxicated.

The only safe way to know if you’re drunk is by blowing a breathalyzer test.

Dangers of Being Drunk

Binge drinking is very common and shouldn’t be discounted for its dangers. It can cause health issues, promote dangerous behavior or even cause death. If someone passes out, it’s potentially deadly for him to be on his back because it’s possible that he'll vomit but be too drunk to wake and turn. Vomiting when passed out is known to drown or choke drunks, and it can be fatal.