The lab has been abuzz with the latest discovery of a silly cell formatting bug in Excel 2007. (Apparently this does not happen in earlier versions of Excel; it certainly doesn’t exist in Excel 2004.)

Here it is: if you enter “=65535*1″ as a cell formula, you do not get the expected result of 65535 as the value of the cell, but rather you get 100000.

Microsoft is aware of the problem but the explanation posted is a little vague; Joel Spolsky has a much better article explaining the bug and how it has to deal with the specifics of floating point representations on modern computer architectures.

References

  1. Molhan Serry, microsoft.public.excel, Bug in Excel 2007, 2007-09-22.
  2. Microsoft Corp., Microsoft Excel Calculation Issue Update, 2007-09-25.
  3. Joel Spolsky, Explaining the Excel Bug, 2007-09-26.