It depends.
If the changes do not include removing rows or columns (or inserting rows or
columns), then you could use a program written by Myrna Larson and Bill
Manville.
You can find a copy on Chip Pearson's site:
http://www.cpearson.com/excel/whatsnew.htm
look for compare.xla
But remember this does a cell-by-cell comparison against two worksheets--not
workbooks. A1 compares to A1, x99 to x99, etc. (So if you insert/delete a
row/column, the comparison goes south very quickly.)
Another option could be to save the worksheets (not workbooks) as a couple .CSV
files. Then use some text comparison file to find the difference. (MSWord has
this ability.)
But this compares text (current values of formulas). Not the formulas
themselves.
And if you have a single unique key in each worksheet that should be compared,
you could have a program that looks for matching keys and if found, does a
comparison between the cells on those rows. (Or adds it as a new key--or marks
it as a deleted record.)
