BAC Calculator

Understand your BAC estimate

Blood alcohol content (BAC) estimates the amount of alcohol in your bloodstream at a given time. The calculator uses your total alcohol intake, body weight, and time since your first drink to estimate how much alcohol has been absorbed and metabolized. Results are estimates, not guarantees, and should never be used to decide if you are safe to drive or operate machinery.

What affects BAC the most

• Body size and sex: Distribution ratios differ between men and women, which changes how alcohol is diluted in the body.
• Drink size and ABV: Two drinks can have very different alcohol content depending on the pour and percentage of alcohol.
• Time since first drink: BAC rises with consumption and then falls as your body metabolizes alcohol.

Legal and health disclaimers

This calculator is for informational purposes only. Impairment can begin below legal limits and laws vary by location. Do not rely on BAC estimates to make legal or medical decisions. If you drink, plan safe transportation and avoid risky activities.

FAQ

How does this BAC calculator work?

We use the Widmark formula with sex-based distribution ratios, your weight, total alcohol consumed, and time since your first drink to estimate BAC.

What counts as one drink?

A standard drink in the US is about 12 oz of beer at 5% ABV, 5 oz of wine at 12% ABV, or 1.5 oz of spirits at 40% ABV. Enter your actual drink size and ABV for more accuracy.

How quickly does BAC drop?

The calculator assumes an average metabolism rate of about 0.015% BAC per hour. Actual rates vary based on body composition, food intake, and other factors.

Is it safe to drive if my BAC is below the legal limit?

Not necessarily. Impairment can begin well below legal limits and laws vary by region. Always use safe alternatives like rideshares or a designated driver.

Does coffee or a cold shower sober me up?

No. Only time helps your body metabolize alcohol. Water, food, or caffeine may make you feel more alert but do not lower BAC.

Is this medical or legal advice?

No. This calculator provides an estimate only and should not be used for medical or legal decisions.