How to Calculate Blood Alcohol Content (Widmark Formula)

How to Calculate Blood Alcohol Content (Widmark Formula)

If you’ve recently consumed alcohol and need to know your blood alcohol content (BAC), you need to use the Widmark Formula. Here are the steps you’ll need to accurately calculate your BAC.

Essential Equipment

To calculate your BAC level, you’ll need to gather the necessary equipment. Here’s what you’ll need:

• BAC chart with corresponding gender and body weight
• Decimal calculator
• Drink volume - ounces of beverage consumed and alcohol percentage of beverage consumed

Steps

1. Multiply the number of ounces of span type="drink consumed" by the percentage of alcohol by volume. Then divide this number by the total amount of body weight in lbs.
2. Look up BAC chart, subtract .015 from this multiplied number for females or .017 for males.
3. Subtract the number from step 2 from the number from step 1.
4. Result is your blood alcohol content.

Example

Let’s say you’re a 140lbs female. You just drank one 12oz beer with 5% alcohol by volume. To calculate your BAC, follow these steps:

1. Multiply 12 x 0.05 = 0.60
2. Divide 0.60 by 140 = 0.004286
3. Subtract 0.015 from 0.004286 = 0.001786
4. Subtract 0.001786 from 0.004286 = 0.0025

Your BAC is 0.0025.

Calculating Your Blood Alcohol Content Using the Widmark Formula

Knowing your blood alcohol content (BAC) is important for assessing your alcohol consumption, especially when engaging in activities like driving. Use the Widmark formula to calculate your BAC. Here’s how:

Step 1: Gather Your Information

You’ll need to know the amount of liquid you’ve consumed, its alcohol content, your weight, and your gender.

Step 2: Calculate Your Volume Distribution Ratio

To do this, you must first calculate your body's volume distribution ratio. It varies between men and women and is calculated as follows:

• For males, use the following formula:
  Volume Distribution Ratio = 0.68 (your weight in kilos) + 0.75
• For females, use the following formula:
  Volume Distribution Ratio = 0.55 (your weight in kilos) + 0.75

Step 3: Calculate Your BAC Level

Once you’ve determined your volume distribution ratio, you’ll be able to use the Widmark formula itself to find your BAC.

It’s calculated as follows:
BAC = (the amount of alcohol consumed in grams/volume distribution ratio) x 100

Step 4: Interpret Your Results

Knowing your BAC is important for ensuring your safety. BAC levels lower than 0.08% are generally considered legal for normal operations, while 0.08% and above is an indication) of impairment.

How to Calculate Blood Alcohol Content (BAC)

Blood alcohol content (BAC) measures your body's concentration of alcohol and can be calculated to help determine if you are legally impaired. To calculate your blood alcohol content with the Widmark Formula, follow the steps below.

Steps to Calculate Blood Alcohol Content:

1. Measure the amount of drinks consumed. Make sure to include the type and size of each beverage. It's important to note that different types of alcoholic drinks contain different amounts of alcohol.
2. Convert what you drank into a liquid measure in ounces. When determining the size of a drink, use the following guidelines:
   • A 12-ounce regular beer is equivalent to one standard drink.
   • A 5-ounce glass of wine is equivalent to one standard drink.
   • A 1.5-ounce shot of 80-proof liquor is equal to one standard drink.
3. Multiply the ounces of liquid consumed by the strength of the alcohol. To get the strength of the alcohol, divide the proof of the beverage by two. For example, 80-proof vodka divided by two would result in 0.4.
4. Calculate your body weight in pounds.
5. Divide the result from step three by your body weight in pounds.
6. Multiply the result from step five by 0.73 to calculate your BAC.

Keep in mind that since there are many factors that contribute to your BAC, this formula is an estimate of your blood alcohol level. Your actual BAC may vary due to gender, body type and other factors.

Calculating Blood Alcohol Content

Determining your Blood Alcohol Content (BAC) can be important to know in social and legal situations. BAC is a percentage measured by the amount of ethanol in your blood. You can use the Widmark Formula to accurately calculate your BAC.

Instructions

1. Gather the necessary information. To calculate your BAC you need to know the type and quantity of the alcoholic beverage, your body weight and gender. Depending on the type of drink, you may also need to know when you finished drinking and its alcohol percentage.
2. Convert units. If your body weight is not in kilograms, convert it from pounds and ounces using a converter found online. If the beverage is not listed in liters, convert it from ounces using a converter found online.
3. Determine Widmark factor. Each gender has their own Widmark factor. Subtracting 0.016 from your Widmark factor will give you the Widmark adjusted factor. For males use a Widmark factor of 0.68 and Adjusted Widmark factor of 0.664. For females use a Widmark factor of 0.55 and Adjusted Widmark factor of 0.534.
4. Calculate BAC. Take the total ounces of alcohol consumed, multiply by 0.8 and divide that number by your body weight in kilograms. Multiply this number by the Adjusted Widmark Factor (AWF) to get your BAC.

For example, a male who is 72 kilograms and has drank 1 liter of beer which was 5% alcohol would calculate their BAC like this: 1 liter x 0.8 = 0.8 liters of pure alcohol. 0.8 liters of pure alcohol / 72 kilograms = 0.011. Multiply by the Adjusted Widmark Factor of 0.664 and you get your BAC of 0.00732.