Blood Alcohol Content (BAC) Calculator

Estimate blood alcohol content using the Widmark formula. This is a rough educational estimate only — see the disclaimer below.

Details

Sex

Weight units

Body weight

Standard drinks consumed

One standard drink ≈ 14 g of pure alcohol (12 oz beer at 5%, 5 oz wine at 12%, or 1.5 oz spirits at 40%).

Hours since first drink

Important disclaimer

This calculator gives a rough mathematical estimate using the Widmark formula. Actual BAC is affected by many factors it cannot account for — food intake, medications, metabolism, drink strength, and individual physiology. It is not accurate enough for legal, medical, or safety decisions. Never use it to decide whether it's safe to drive — if you've been drinking, don't drive. When in doubt, use a certified breathalyzer or call a taxi/rideshare.