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Blood Alcohol Calculator

Estimate your blood alcohol content (BAC) based on drinks, weight, gender, and time. Understand impairment levels.

BAC Worksheet
Disclaimer: This is an estimate only. Do not drink and drive. Individual metabolism varies.

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Understanding Blood Alcohol Content

BAC measures how much alcohol is in your blood. It's affected by how much you drink, your weight, gender, and time.

Important: This is an estimate only. Individual metabolism varies. Never drink and drive.

BAC Impairment Levels

  • 0.02-0.03%: Slight relaxation, mild mood changes
  • 0.05-0.06%: Lowered inhibitions, impaired judgment
  • 0.08%: Legal limit - impaired coordination, reaction time
  • 0.10-0.12%: Significant impairment, slurred speech
  • 0.15%+: Major impairment, risk of blackout

Standard Drink Sizes

  • 12 oz regular beer (5% alcohol)
  • 5 oz wine (12% alcohol)
  • 1.5 oz spirits (40% alcohol)
  • 8-9 oz malt liquor (7% alcohol)

Factors Affecting BAC

  • Body weight: Lower weight means higher BAC from the same number of drinks — alcohol is distributed through body water
  • Biological sex: Women typically reach higher BAC from the same drinks due to lower body water percentage and different enzyme levels
  • Food: Eating before or while drinking slows absorption significantly. A full stomach can reduce peak BAC by up to 50%
  • Drinking speed: Faster consumption produces higher peak BAC. The body eliminates alcohol at a fixed rate (~0.015%/hour) regardless of how much you consume
  • Drink strength: Craft beers (7-12% ABV), strong cocktails, and wines vary widely from standard drink assumptions

How Long to Sober Up

The body metabolizes approximately 0.015% BAC per hour — roughly one standard drink per hour. There is no way to speed this up. Coffee, cold showers, and food do not lower BAC faster; only time works.

  • BAC of 0.08% → approximately 5.3 hours to reach 0.00%
  • BAC of 0.12% → approximately 8 hours to reach 0.00%
  • BAC of 0.15% → approximately 10 hours to reach 0.00%

These are estimates. Sleep does not accelerate metabolism — you can still be legally impaired the morning after heavy drinking.

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Frequently Asked Questions

How long does it take to sober up?

The body removes about 0.015 percent BAC per hour, so a BAC of 0.08 percent, the legal driving limit in most US states, takes roughly 5 to 6 hours to reach zero. Coffee, cold showers, exercise and drinking water do not speed this up. Only time lowers blood alcohol content.

What counts as one standard drink?

In the US, one standard drink holds about 14 grams of pure alcohol. That equals 12 ounces of 5 percent beer, 5 ounces of 12 percent wine or 1.5 ounces of 40 percent spirits. Stronger beers and large pours count as more than one drink, which raises BAC faster than the glass count suggests.

Why do women reach a higher BAC than men from the same drinks?

Women generally have a lower share of body water and more body fat, so alcohol spreads through a smaller volume of water and reaches a higher concentration. Women also tend to produce less alcohol dehydrogenase, an enzyme that starts breaking down alcohol in the stomach before it reaches the bloodstream.

Does eating before drinking lower BAC?

Yes. Food in the stomach slows alcohol absorption, lowering the peak BAC and delaying when it is reached. A large meal before drinking can cut peak BAC by roughly 30 to 50 percent compared with drinking on an empty stomach. Food does not change how fast the body clears alcohol once absorbed.