Blood Alcohol Content (BAC) Estimator
Estimate your BAC using the Widmark formula. This is for informational purposes only.
How to Use the Free Online BAC Calculator
Enter your biological sex and body weight (in kg or lbs).
Enter the number of standard drinks you have consumed.
Enter the total number of hours that have passed since you had your first drink.
The calculator will automatically provide an estimated Blood Alcohol Content (BAC) percentage, for free.
Frequently Asked Questions
Is this BAC calculator accurate?
This online calculator uses the Widmark formula, a widely accepted method for estimating BAC. However, it is only an estimate. Actual BAC can be affected by many factors such as metabolism, food intake, and medications. It should not be used for legal purposes or to determine if you are safe to drive.
What is a 'standard drink'?
A standard drink in the United States contains about 14 grams of pure alcohol. This is roughly equivalent to one 12-ounce beer (5% ABV), one 5-ounce glass of wine (12% ABV), or one 1.5-ounce shot of distilled spirits (40% ABV).
Is this tool free to use?
Yes, this is a completely free online tool for informational purposes. No fees or subscriptions are required.