Originally Posted by DevilsAdvocate
At least in the Excel 2007 version I have, there is no "guess" input in the rate function. There is a "guess" in the IRR function, but to be honest that seems to be legacy as the IRR function always returns the right value for me. I just checked. If I do -1000 in year 0, and +1 billion in year 50 (with 0 for the cash flows in between), the irr function gives 31.83% (I rounded incorrectly when I said 31.82%, it's 31.8257%)
So that's two quick and easy ways to find an answer in excel that excel can't seem to solve on its own.