Blood Alcohol Calculator

Estimate your Blood Alcohol Content (BAC) based on your weight, gender, number of drinks, and how much time has passed. This tool is for educational purposes — never drink and drive.

Estimated BAC
Status
Time Until Sober

This calculator provides estimates and is for informational purposes only. Consult a healthcare professional for medical advice.

How It Works

This calculator uses the Widmark formula to estimate your Blood Alcohol Content: BAC = (Drinks × 14g) ÷ (Weight in kg × Gender Factor × 10) − (0.015 × Hours). The gender factor accounts for differences in body water content — males average 0.68 and females 0.55. Your body metabolizes alcohol at roughly 0.015% BAC per hour.

A "standard drink" is defined as 14 grams of pure alcohol, which is roughly equivalent to 12 oz of beer (5% ABV), 5 oz of wine (12% ABV), or 1.5 oz of distilled spirits (40% ABV). Individual metabolism, food intake, and medications can all affect your actual BAC.

Frequently Asked Questions

What BAC level is considered legally drunk?
In most U.S. states, a BAC of 0.08% or higher is considered legally intoxicated for drivers over 21. Many countries have lower limits, and some jurisdictions set the limit at 0.05%. For commercial drivers, the limit is typically 0.04%.
How long does it take for alcohol to leave my system?
Your body metabolizes alcohol at an average rate of about 0.015% BAC per hour. This rate is relatively constant and cannot be significantly sped up by coffee, cold showers, or exercise. The only reliable method is time.
Is this calculator accurate enough for legal decisions?
No. This calculator provides rough estimates only. Actual BAC depends on many individual factors including body composition, food intake, metabolism rate, and medications. Never rely on any calculator to determine if it is safe to drive.

Related Calculators

Water Intake Calculator

Find your daily hydration needs

BMI Calculator

Check your body mass index

Calorie Calculator

Estimate daily calorie needs

Pace Calculator

Calculate running or walking pace