Drunk Drive Calculator

The Drunk Drive Calculator estimates your Blood Alcohol Content (BAC) based on your body weight, biological sex, and alcohol consumption. This tool helps drivers determine their fitness to drive and avoid legal trouble. Whether you had a quick drink after work or a long night out, this calculator provides a quick safety check.

Enter your body weight in pounds (lbs)
Number of hours you've been drinking
One standard drink = 14g of pure alcohol (12oz beer, 5oz wine, 1.5oz spirits)

How Blood Alcohol Content Is Calculated

Blood Alcohol Content (BAC) is the percentage of alcohol present in your bloodstream. To find this number, the calculator uses the Widmark Formula, which accounts for how your body absorbs and processes alcohol.

BAC = (Alcohol Consumed (oz) × 5.14) / (Weight (lbs) × r) - (0.015 × Hours)

Where:

  • Alcohol Consumed: Total ounces of pure alcohol ingested.
  • Weight: Your body weight in pounds.
  • r: Gender constant (0.73 for men, 0.66 for women).
  • 0.015: Average alcohol elimination rate per hour.
  • Hours: Time spent drinking.

The calculation first spreads the alcohol through your body water, which differs by biological sex. Then, it subtracts the alcohol your liver metabolizes over time. This provides a scientifically backed estimate of your current impairment level.

What Your Blood Alcohol Content Means

Your BAC number represents your level of intoxication and affects your reaction time and judgment. **Safe Zone (0.00% - 0.02%)** usually means you are functioning normally with little to no impairment. **Legal Risk Zone (0.05% - 0.08%)** indicates reduced coordination and judgment, meaning you may be unsafe to drive even if below the legal limit. **Legally Drunk (0.08% and above)** means you are legally intoxicated in all US states and must not drive.

Time Until Sober

Use the "hours until sober" result to plan when you can safely drive. This figure estimates how long it takes for your BAC to return to 0.00% based on average metabolism rates.

Disclaimer: This calculator is for informational purposes only and does not constitute legal or medical advice. Actual BAC can vary based on health factors and food intake. Never drink and drive.

To stay safe, always add a buffer of one or two extra hours to your "time until sober" result before getting behind the wheel.