Free BAC calculator to estimate blood alcohol content based on drinks consumed, body weight, gender, and time elapsed since drinking.
This is an estimate. Actual BAC varies with food, medications, liver health, drinking pace, and individual metabolism. When in doubt, do not drive — use a rideshare or designated driver.
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Wondering about your BAC? This calculator estimates blood alcohol content based on drinks consumed, body weight, gender, and time since drinking. Remember: this is an estimate only—individual metabolism varies significantly.
BAC measures alcohol in your bloodstream as a percentage. 0.08% is the US legal limit for driving. Alcohol is metabolized at roughly 0.015% per hour regardless of body size. The Widmark formula estimates BAC using body weight, gender (women have lower water content), and alcohol consumed.
Widmark Formula
This calculator is for educational purposes.
When in doubt, don't drive. Use rideshare or designated driver.
Actual BAC can vary significantly from estimates.
Make informed decisions about driving
Understand how alcohol affects you
Estimate time until sober
Learn about impairment levels
Promote responsible drinking
A standard drink contains 14 grams of pure alcohol: 12 oz beer (5%), 5 oz wine (12%), or 1.5 oz spirits (40%). Many drinks contain more—a pint of craft beer or large wine pour may equal 2+ standard drinks.
It provides estimates only. Actual BAC varies based on food consumption, medications, liver health, drinking speed, and individual metabolism. Never rely solely on calculations to determine if you're safe to drive.
Women typically have higher BAC from the same drinks due to lower body water percentage (which dilutes alcohol) and different enzyme levels. The Widmark 'r' factor accounts for this.
Your body eliminates about 0.015% BAC per hour. From 0.08%, expect 5+ hours to reach zero. Nothing speeds this up—coffee, food, or water won't help. Only time reduces BAC.