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Number of Drinks and Blood Alcohol Content (BAC)

Information For Women

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Updated November 14, 2010

Here is a general guide to estimating your Blood Alcohol Content (BAC), based on your body weight and speed of drinking:

One Drink

One American standard drink will, on average, produce a Blood Alcohol Content of about 0.02. Most light and moderate drinkers will feel some subtle effects at this level.

After a woman has one standard drink…

  • If she weighs 100 pounds, she will have a Blood Alcohol Content of 0.05. If she drinks it over one hour, she will have a BAC of 0.03, and if she drinks it over two hours, she will have a BAC of 0.01. Only after three hours will she have a BAC of 0.00.
  • If she weighs 150 pounds, she will have a Blood Alcohol Content of 0.03. If she drinks it over one hour, she will have a Blood Alcohol Content of 0.01, and after two hours, she will have a BAC of 0.00.
  • If she weighs 200 pounds, she will have a Blood Alcohol Content of 0.02. If she drinks it over one hour, she will have a Blood Alcohol Content of 0.008, and after two hours, she will have a Blood Alcohol Content of 0.00.

So after just one drink, even larger women take around two hours for their BAC to return to zero.

Two Drinks

Two American standard drinks will, on average, produce a Blood Alcohol Content of about 0.04, and most light and moderate drinkers will feel relaxed at this level. Reaction times will be slowed, and fine motor skills will be affected to the extent that driving will be impaired.

After a woman has two standard drinks…

  • If she weighs 100 pounds, she will have a Blood Alcohol Content of 0.08. If she drinks it over one hour, she will have a Blood Alcohol Content of 0.07, and if she drinks it over two hours, she will have a Blood Alcohol Content of 0.05. After three hours, her BAC will have dropped to 0.04. After four hours, it will be down to 0.02, and after five hours, it will have lowered to 0.005. Only after six hours will she have a Blood Alcohol Content of 0.00.
  • ]If she weighs 150 pounds, she will have a Blood Alcohol Content of 0.06. If she drinks it over one hour, she will have a Blood Alcohol Content of 0.04, and after two hours, she will have a Blood Alcohol Content of 0.03. After three hours, her Blood Alcohol Content will be down to 0.01, and after four hours, it will be at 0.00.
  • If she weighs 200 pounds, she will have a Blood Alcohol Content of 0.05. If she drinks it over one hour, she will have a Blood Alcohol Content of 0.03, and after two hours, she will have a Blood Alcohol Content of 0.02. After three hours, her Blood Alcohol Content will be down to 0.001, and after four hours, it will be at 0.00.

So after two drinks, it takes four to six hours for your Blood Alcohol Content to return to zero.

Three Drinks

Three American standard drinks will produce, on average, a Blood Alcohol Content of about 0.06, at which point the negative effects of alcohol become apparent. At this level, judgment will be impaired, often affecting people’s ability to make rational decisions, particularly around risk taking activities such as driving and continuing to drink. Perception, learning, memory, coordination, sexual arousal, alertness and self-control will also be impaired.

After a woman has three standard drinks…

  • If she weighs 100 pounds, she will have a Blood Alcohol Content of 0.14. If she drinks it over one hour, she will have a Blood Alcohol Content of 0.12, and if she drinks it over two hours, she will have a Blood Alcohol Content of 0.10. After three hours, her Blood Alcohol Content will have dropped to 0.09, after four hours, it will be down to 0.07, and after five hours, it will have lowered to 0.06. After six hours will she have a Blood Alcohol Content of 0.04, and only after a whopping nine hours will it be down to 0.00.
  • If she weighs 150 pounds, she will have a Blood Alcohol Content of 0.10. If she drinks it over one hour, she will have a Blood Alcohol Content of 0.08, and after two hours, she will have a Blood Alcohol Content of 0.06. After three hours, her Blood Alcohol Content will be down to 0.05, and after four hours, it will be at 0.03. After six hours, her Blood Alcohol Content will be down to 0.00.
  • If she weighs 200 pounds, she will have a Blood Alcohol Content of 0.07. If she drinks it over one hour, she will have a BAC of 0.05, and after two hours, she will have a Blood Alcohol Content of 0.04. After three hours, her Blood Alcohol Content will be down to 0.02, and after five hours, it will be at 0.00.

Three to Eight Drinks

The effects noted at the three drink level (or a Blood Alcohol Content of 0.06) will become more pronounced with each additional drink. By the time you reach a Blood Alcohol Content of about 0.12, vomiting usually occurs, unless this level is reached slowly, or you already have tolerance to alcohol. Vomiting is the body’s first line of defense against overdose.

  • This Blood Alcohol Content level would be reached by a 100-pound woman quickly, after only three to four drinks over two hours.
  • A 150-pound woman would reach this level if she had six drinks over three to four hours.
  • A 200-pound woman would reach this level if she drank six to seven drinks over one to two hours. If she drank more slowly, it might take seven or eight drinks to reach this level over two to four hours.

At the point where your Blood Alcohol Content reaches 0.15, most people have difficulty walking in a straight line. On average, women would reach this level after about five to six drinks over one to four hours.

Five to 10 Drinks

With a BAC of 0.2, most people experience a “blackout,” having no memory of all or part of what happened during the period their BAC was at this level. In younger women, this level can be fatal.

Women generally reach this level after drinking five to 10 drinks over one to four hours.

Seven to 15 Drinks

At the Blood Alcohol Content level of 0.3, most people lose consciousness.

15-Plus Drinks

The Blood Alcohol Content level of 0.45 is the average fatal dose for adults, at which point breathing and heartbeat stop.

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