BAC Calculator

The “BAC Calculator” tool is a helpful application designed to estimate your Blood Alcohol Content (BAC) based on your body weight, gender, the type and quantity of alcoholic beverages consumed, and the time elapsed since your last drink.

Blood Alcohol Content Calculator

Blood Alcohol Content Calculator

How to Calculate Blood Alcohol Content?

To calculate Blood Alcohol Content (BAC), you can use the Widmark formula, which is one of the commonly used methods. Please note that BAC calculation can be a complex process, and various factors can influence the accuracy of the result. The Widmark formula provides an estimate based on certain assumptions. Here’s the basic form of the formula:

BAC = (A × 5.14 / (W × r)) − 0.015 × H


  • A is the total alcohol consumed in grams.
  • W is the body weight in kilograms.
  • r is the alcohol distribution ratio (0.68 for men and 0.55 for women).
  • H is the number of hours since the last drink.

Keep in mind that this formula assumes average alcohol metabolism rates and may not be accurate for everyone. Additionally, it doesn’t account for other factors such as individual variations in metabolism, tolerance, or the presence of any medication or health conditions. It’s always advisable to drink responsibly and not rely solely on BAC calculations for determining sobriety.

It’s important to note that laws and regulations related to BAC limits may vary by jurisdiction. Always comply with local laws and guidelines regarding alcohol consumption and driving.

What is a Standard Drink?

The definition of a standard drink may vary slightly depending on the country, but it typically represents a fixed amount of alcohol. In the United States, a standard drink is generally defined as containing about 14 grams (0.6 ounces) of pure alcohol.

It’s important to note that the actual volume or size of a standard drink can vary depending on the alcohol concentration (percent alcohol by volume) of the beverage. For example, a standard drink of beer, wine, or spirits may have different volumes due to variations in alcohol content. Typically, a standard drink in the U.S. is considered to be:

  • 12 ounces (355 milliliters) of regular beer with about 5% alcohol by volume.
  • 5 ounces (148 milliliters) of wine with about 12% alcohol by volume.
  • 1.5 ounces (44 milliliters) of distilled spirits (e.g., vodka, whiskey, rum) with about 40% alcohol by volume.

These values are approximate and can vary depending on the specific brand, country, or local regulations.

Standard Drink TypeSizePercent Alcohol
Beer12 oz4-6%
Wine5 oz12-15%
Spirits1.5 oz40-50%