Test weight is used as an indicator of general grain quality and is a measure of grain bulk density. Test weight, but not overall grain weight, normally increases during drying. Erroneous calculations using test weights can incorrectly infer that drying systems that increase test weight also increase the number of bushels that can be sold. This bulletin explains the use of test weight in the grain industry, how it can be used to determine grain value, and why some calculations involving test weight can be deceptive.