BAC Calculator
Estimate your blood alcohol content with the Widmark formula using your weight, gender, number of drinks, drink type, and time since your first drink.
Estimated BAC
1.065
Impairment Level
Dangerous
Estimated Time Until Sober
71.0 hours
Driving Status
Over the legal driving limit
This is an estimate only. Do not drink and drive. BAC varies by individual.
Based on 2 drinks, about 28.0 g of alcohol, 180 lbs body weight, and 2.00 hours elapsed.
How to Use
- Choose your gender and enter your body weight in pounds or kilograms.
- Select a drink type, then enter how many drinks you had. For cocktails, customize the size and alcohol percentage.
- Enter the number of hours since your first drink.
- Review your estimated BAC, impairment level, time until sober, and whether you are over the common 0.08 driving threshold.
Frequently Asked Questions
How is BAC estimated?
This calculator uses the Widmark formula, which estimates BAC from the amount of alcohol consumed, your body weight, sex-based distribution ratio, and time for alcohol elimination. It is only an approximation.
Is one drink always the same?
No. Drink sizes and alcohol percentages vary. A standard U.S. drink contains about 14 grams of pure alcohol, which is roughly equal to a 12-ounce beer at 5%, 5 ounces of wine at 12%, or a 1.5-ounce shot at 40%.
Can I drive if my BAC is below 0.08?
Not necessarily. Many people are impaired well before 0.08 BAC, and some places use stricter legal thresholds. The safest choice is not to drive after drinking.
Why is this only an estimate?
Actual BAC depends on food intake, medications, metabolism, hydration, drinking pace, health conditions, and individual biology. Breath or blood testing is the only way to measure BAC more directly.