What counts as a 'standard drink'?

A standard drink typically contains about 14 grams of pure alcohol. This is roughly 12 oz of regular beer (5%), 5 oz of wine (12%), or 1.5 oz of distilled spirits (40%).

How fast does the body process alcohol?

On average, the body metabolizes alcohol at a rate of approximately 0.015% BAC per hour. Nothing can speed up this process—not coffee, cold showers, or exercise.

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Health & Fitness

BAC Calculator – Blood Alcohol Monitoring Service | CalcTools

Estimate your Blood Alcohol Content (BAC) based on consumption, gender, and body weight. Understand the impact of alcohol on your system.

Alcohol affects every person differently based on their size, gender, and how quickly they consume drinks. Understanding your Blood Alcohol Content (BAC) is vital for safety and legal compliance. While no online tool can replace a professional breathalyzer or provide a legal guarantee of sobriety, our BAC Calculator uses the scientifically recognized Widmark Formula to provide an estimate of how much alcohol is currently in your bloodstream. Remember: when in doubt, never get behind the wheel.

Weight (kg)

Number of Standard Drinks

Hours since first drink

Estimated BAC

0.044%

Estimated BAC is 0.044%

Weight (kg)70

GenderMale

Number of Standard Drinks2

Hours since first drink1

This is an estimate. Do not drive if you have consumed alcohol.

How it Works

The tool uses the Widmark Formula, which calculates alcohol concentration based on the mass of alcohol consumed and the patient's body water (determined by weight and gender), then subtracts the average rate of metabolism over time.

Calculation Formula

Widmark Formula

Calculation Examples

1. **Moderate**: A 80kg male who has 3 beers over 2 hours will have an estimated BAC of **~0.03%**.

Why use this tool in your daily life?

Responsibility starts with information. This tool helps you understand how different drinks affect your unique physiology, empowering you to make safer choices for yourself and your community.