You can estimate the percent of alcohol in the blood by the number of drinks in relation to body weight. You should remember this is just an estimate. Many factors such as amount and type of food consumption, prior exposure to alcohol, medical issues, gender differences, and time of consumption can change the calculations up or down. To make an estimate:
1. Count your drinks (1 drink equals one ounce of 100-proof liquor, one five-ounce glass of table wine or one twelve ounce bottle of regular beer).
2. Use the following chart and under number of “drinks” and opposite “body weight” find the percent of blood alcohol listed.
3. Subtract from this number the percent of alcohol “burned up” during the time elapsed since your first drink. This figure is .015% per hour. (Example: 180 lb. man has 8 drinks in 4 hours / .167% minus (.015x4) = .107 %)