Blood Alcohol Content Calculator

Calculate your BAC using the Widmark formula. This tool provides an assessment of blood alcohol levels based on internationally recognized standards.

Patient Information

drinks

1 standard drink = 14g pure alcohol

hours

Medical Notice: This calculator provides general information for educational purposes only. Never drive after consuming alcohol. Individual factors affect actual BAC. Full disclaimer

Fill in your information to see BAC results

Standard Drink

One standard drink contains 14 grams of pure alcohol: 12 oz beer (5% ABV), 5 oz wine (12% ABV), or 1.5 oz spirits (40% ABV).

Elimination Rate

The average person eliminates alcohol at 0.015% BAC per hour. This rate varies by individual metabolism and liver function.

Legal Limits

In the US, the legal limit is 0.08% BAC. Many countries have lower limits, and some have zero tolerance policies.

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Widmark Formula

BAC = (A / (r × W)) - (β × T)
  • • A = Alcohol consumed (grams)
  • • r = Widmark factor (0.71 for men, 0.58 for women)
  • • W = Body weight (kg)
  • • β = Elimination rate (0.15 g/L/hr average)
  • • T = Time elapsed (hours)

BAC Effects by Level

0.01-0.05% Mild relaxation
0.06-0.20% Impaired
0.20-0.30% Severe intoxication
0.30-0.40% Life-threatening
> 0.40% Potentially fatal

Medical Reference

Wikipedia Reference

This calculator implements the Widmark formula for Blood Alcohol Content calculation as described in the Wikipedia article on BAC.

View Wikipedia Article
Author

Dr. Beltrán J.F.