I'm always making reports in excel, usually when outputting to CSV. Until now, I would go and look up how to use Powershell to convert this, but sometimes I just need to throw something together quickly, and this is what I learned to do in Excel to convert a whole column from one thing to another:
I'm running Office 2010, by the way.
Put the number 1024 into a cell that's not in the column you're going to convert.
Now, copy that one cell.
Select the column that you want to convert.
Right-click, select Paste Special, Paste Special AGAIN, then "Divide".
Looking at the menu where you choose divide, you'll notice other mathematical operation. Sure enough, you can use this same method to add, subtract, or multiply an entire selection of values by whatever number you have copied.