comotoman -

Anybody have any ideas? <

Please be more specific.

The RAND worksheet function returns numbers with 15 significant digits.

Your formula "=rand()*(100-1)+1" will also have 15 significant digits.

If you examine a sequence of several hundred or several thousand or several
hundred thousand, you will not see any duplicates.

The above if formulas work when i test the cells without Rand, but do not
work when i enter the rand formula from above. <

What do you mean by "do not work"?

It would seem that it does not recalculate after each change. <

After each change of what? That is, what are you changing?

- Mike
www.mikemiddleton.com