|Please keep this in mind if you choose to go with Humar's formula that contains the TODAY() function:|
The TODAY() function is consider "volatile" by Excel. What this means is that every time you open a file that contains the TODAY() function, it will force a calculation in that cell and Excel will consider the file as being "changed".
When you try to close the file, Excel will ask you if you want to save the changes, even if you made no "manual" changes to it. This can be a bit of a pain.
I recently thought that the TODAY() function would make a few of my spreadsheets easier to use, when it fact it got to be extremely inconvenient.
Sometimes I open these spreadsheets just to look at some data and other times I right-click the file name and choose Print. In both of these cases, Excel asks me if I wanted to "Save the Changes" even though I haven't done anything.
I also found that it was confusing my clients because they didn't know why they were being asked to save the changes after just looking at the contents of the files.