Blood/Breath Alcohol Concentration (BAC) calculator

Using the BAC calculator | What can affect your BAC? | Disclaimer

Blood/Breath Alcohol Concentration (BAC) is the amount of alcohol in the bloodstream or on one's breath. BAC is expressed as the weight of ethanol, measured in grams, in 100 milliliters of blood, or 210 liters of breath. BAC can be measured by breath, blood, or urine tests.

Using the BAC calculator

Use this calculator to instantly compute your estimated blood/breath alcohol concentration.

Instructions:  Please select weight, drinks consumed, time period and gender and click the "compute your BAC" button:

Weight: (pounds)
Drinks consumed: (12 oz. beer or equivalent)
Over time period: (hours)

Your BAC will be:


This BAC calculator is "JavaScript-based" and your browser will need JavaScript enabled to work. This calculator may not work with some older browsers that do not support JavaScript.

What can affect your BAC?


Your actual BAC is dependent on many complex factors, including your emotional and physical condition and health, and what you've recently ingested (including food, water, medications and other drugs).

You should not consider this to be a guideline for how much you can drink and still drive responsibly, or avoid being arrested! The best policy is don't drink and drive. Period.

NOTE: The basic formula for estimating a person's blood/breath alcohol concentration comes from the National Highway Traffic Safety Administration.