Similar to IRR, the XIRR formula will give results whether the investment amounts are the same or different.

Be sure the cell range in the IRR formula always starts with the lump-sum cell in Column C and ends with the age you want. For example, =IRR (C1:C18) would be the formula used at age 80 in Column D.

Example Let me pose an exaggerated theoretical example of why you should evaluate managers using the time weighted rate of return rather than the IRR. Let’s say you have two managers, A and B.