BAC Calculator

Estimate your Blood Alcohol Content based on drinks, weight, and time elapsed.

lbs
Beer
12oz, 5%
Wine
5oz, 12%
Liquor
1.5oz, 40%
Custom
Set your own
drinks
hours
hours

How BAC is Calculated

This calculator uses the Widmark formula, the standard method for estimating Blood Alcohol Content. The formula accounts for the amount of alcohol consumed, body weight, gender differences in body water content, and time elapsed for metabolism.

BAC = (Alcohol in grams / (Body weight in grams x r)) - (0.015 x hours)

r = 0.68 (men) or 0.55 (women)
Standard drink = 14 grams of alcohol
Metabolism rate = 0.015% per hour

Standard Drink Equivalents

  • Beer: 12 oz at 5% ABV = 14g alcohol
  • Wine: 5 oz at 12% ABV = 14g alcohol
  • Liquor: 1.5 oz at 40% ABV = 14g alcohol

Important Disclaimer

  • This is an estimate only. Actual BAC can vary significantly based on individual factors including metabolism, food intake, medications, health conditions, and more.
  • Do not use this to determine if you are safe to drive. Even low BAC levels impair driving ability. The only safe amount of alcohol for driving is zero.
  • This is not legal or medical advice. This calculator is for educational and informational purposes only.
  • If you have been drinking, do not drive. Use a designated driver, rideshare service, taxi, or public transportation.
  • Breathalyzer and blood tests are the only accurate methods to determine actual BAC levels.