Question: what is the difference between alcohol by weight and volume?
Answer: A pint of alcohol, on the other hand, weighs only 0.79 pound. So a beer with an alcohol content of 3.2 percent by weight is actually 4 percent by volume. A beer that is 4 percent by weight is actually 5 percent by volume. ... To convert an alcohol-by-volume reading to its alcohol-by-weight equivalent, multiply by 0.80.