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CalcRiver

BAC Calculator

Estimate your Blood Alcohol Content (BAC) based on your weight, gender, and drinks consumed. Check if you are within legal driving limits and estimate time to sober up.

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How BAC is Calculated

This Blood Alcohol Content calculator uses the Widmark Formula, the most widely accepted method for estimating BAC.

The formula considers:

  • Alcohol Consumed: Volume × ABV × Density of Alcohol (0.789 g/ml).
  • Body Weight: Heavier individuals have more body fluid to dilute alcohol.
  • Gender Constant (r): Men (0.68) generally have more water content than women (0.55).
  • Elimination Rate: The body processes alcohol at an average rate of 0.015% per hour.

Standard Drink Sizes

It's easy to underestimate intake. One "standard drink" contains about 14 grams of pure alcohol.

  • Beer: 12 fluid ounces (355 ml) at 5% ABV.
  • Wine: 5 fluid ounces (148 ml) at 12% ABV.
  • Distilled Spirits: 1.5 fluid ounces (44 ml) at 40% ABV (80 proof).

Note: Craft beers (IPA, Stout) often have much higher ABV (7-9%), counting as 1.5 to 2 standard drinks per bottle.

Limits and Safety

  • 0.00 - 0.04%: Mild relaxation, slight body warmth. Generally safe for most activities.
  • 0.04 - 0.07%: Lowered inhibitions, minor impairment of reasoning and memory. Driving skills may be affected.
  • 0.08%+: Legally Intoxicated. Significant impairment of motor coordination and balance. Illegal to drive in the US/UK.
  • 0.20%+: Confusion, dazed state, blackout likely. Nausea and vomiting common.

Disclaimer: This calculator is for educational and entertainment purposes only. It provides an estimate based on averages. Real-world BAC depends on individual metabolism, food intake, genetics, and medication. Do not rely on this tool to determine if you are fit to drive. Never drink and drive.

? Frequently Asked Questions

The body eliminates alcohol at a constant rate of about 0.015% BAC per hour. Coffee, showers, or water do not speed up this process; only time works.

Eating *before* drinking slows absorption, keeping your peak BAC lower. Eating *after* you are already drunk does not lower your BAC, though it may help settle your stomach.

Women typically have less body water and less of the enzyme dehydrogenase (which breaks down alcohol) than men, leading to a higher BAC for the same amount of alcohol consumed.

No. While 0.08% is standard in the US and UK, many countries (like Australia, France, Germany) have stricter limits of 0.05%, and some have zero tolerance (0.00-0.02%).