Well, depends on many factors and can vary widely. Especially with DME. Any dry powder and spraymalt especially, is highly effected by humidity. Ever notice how quickly dme gets sticky by just touching it? It is extremely hygroscopic, that is, it very readily absorbs moisture from the air. So, how much will fit in a measuring cup depends on the amount of moisture it has absorbed. Additonally, how much air is trapped in there (and how moist the air is) will also give you variatons from one scoop to the next.
That said, I would gladly try and weigh and measure some for you to get an estimate, unfortunately I do not have any dme on hand.
Sorry, some else perhaps? Maybe weigh a few times and take an average?
Not trying to be a pita but you could get a cheapy plastic kitchen scale for about $5. They are not the most accurate, but they are more accurate than measuring volumetrically. Or you can get a pretty decent digital scale like this for about $25
Given that there are several variables involved in this conversion, IE... humidity, how tightly you pack the DME in the measuring cup etc... it comes out to be about 2.25 cups per pound or .4 lbs per cup.
I just needed a rough estimate. I only need a little wheat DME, around .25-.5#, so I used it to make my starter, so I just wanted to know if pitching my starter alone would add the amount I needed, and it looks like it will. Thanks for the help.