I've run into a terribly confusing thing. I'm using a few formulas with time, and I've got it all worked out. But somehow, when I enter the times 14:30 minus 12:30 (the formula makes appropriate conversions) and then subtract 2 from the difference, I don't get zero...rather I get -2E-15. When I use other values (I tried offsetting both values by one minute), I get the appropriate answer of 0. Any clues on this? Bug in excel? Reply to me if you are interested in helping, I can email you a portion of my spreadsheet.