How do you calculate the alcoholic content of beer?

Alcohol content in beer is measured in %/volume. Multiply the number of units of beer by the % alcohol to get the total volume of alcohol.

12 oz. of 5% beer = 12 x .05 = 0.6 ounces of pure alcohol.

If you do not know the %-age of alcohol, as in home brewing, you would need to test the specific gravity. Testing equipment is available in home brewing catalogs.