BAC Calculator
Estimate your Blood Alcohol Content based on your drinks, weight, and time elapsed.
⚠ Disclaimer
This calculator provides estimates only and should NOT be used to determine whether you are safe to drive or perform any activity. Actual BAC depends on many individual factors not accounted for here. When in doubt, do not drive.
How the BAC Calculator Works
This calculator uses the Widmark formula, the most widely accepted method for estimating Blood Alcohol Content. The formula accounts for the amount of pure alcohol consumed, your body weight, biological sex (which affects body water percentage), and the time elapsed since your first drink.
Your body eliminates alcohol at a roughly constant rate of about 0.015% BAC per hour (approximately one standard drink per hour). This metabolic rate is relatively consistent across individuals, regardless of body size.
A "standard drink" in the US contains about 0.6 oz of pure alcohol — equivalent to a 12 oz beer (5% ABV), a 5 oz glass of wine (12% ABV), or a 1.5 oz shot of spirits (40% ABV).