🍺 BAC Calculator
Blood alcohol content rises with every standard drink and falls about 0.015% per hour as your liver works. The Widmark formula combines your drinks, weight and gender into an estimate of where you stand right now.
This is an estimate, not a legal test: food, health, medication and drink strength all shift the real number, and impairment starts well below any legal limit. If you drank, do not drive — no calculator changes that.
How to use this calculator
Enter your drinks, weight, gender and drinking time to estimate your blood alcohol content.
- Enter your Standard drinks count.
- Enter your Weight in the kg field.
- Select your Gender.
- Enter the Hours drinking and read the headline BAC estimate.
Frequently asked questions
How is BAC estimated?
With the Widmark formula: drinks times 0.6 ounces of pure alcohol times 5.14, divided by weight in pounds times a gender factor, minus 0.015 per hour. A 80 kg man having 3 drinks over 2 hours lands near 0.042 percent.
What counts as one standard drink?
About 0.6 ounces of pure alcohol: a 330 ml regular beer, a 150 ml glass of wine or a 45 ml shot of spirits. Strong craft beers and generous pours count as more than one.
Why do women reach higher BAC than men?
Women typically carry less body water per kilogram, so the same alcohol concentrates more. The formula uses 0.73 for men and 0.66 for women to reflect that.
Can I drive if I am under the legal limit?
Impairment starts well below legal limits, and this is an estimate, not a breathalyzer. If you drank, do not drive. Arrange a ride instead; no calculator makes drinking and driving safe.