How to Calculate Bac Level

Written by wendy rose gould
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How to Calculate Bac Level
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Calculating your BAC (blood alcohol content) takes your age, weight and amount of alcohol you drink in a given time to determine what percentage of your blood contains alcohol. This number is good to know if you plan to drive later. Note that there are many variables that could alter your BAC, including any medication you've taken, the rate your body cleans out alcohol and also how much food or non-alcoholic liquid you've had between, during or after drinks. This process leaves you with an estimation and not an exact BAC number.

Skill level:
Moderately Easy

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Things you need

  • BAC chart

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  1. 1

    Determine how many drinks you had in one hour. One ounce of 100 proof liquor, 147ml of wine and 340gr of beer qualify as one drink each.

  2. 2

    Locate a BAC chart. There are many online that you can print off or refer to when needed; see the Resources section below.

  3. 3

    Choose the weight that is closest to your own and choose the corresponding number of drinks. The number where these two meet is your blood alcohol content.

  4. 4

    For every hour you did not have a drink, subtract 0.015. So if you are a 140 pound female who had three drinks, your BAC is 0.08. If you go three hours without drinking, your BAC is now 0.035 per cent (0.08 - 0.045).

Tips and warnings

  • The legal drinking limit in every state is 0.08 per cent.

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