IRR calculator

IRR is the rate that sets NPV to zero, found here by scanning a rate grid and bisecting every sign change, the same answer a spreadsheet gives for conventional flows. The solver cannot see two roots that share one grid cell, so the sign-change count and the NPV profile below are the honest check: more sign changes than one means more IRRs may exist, and a curve that never crosses zero means no IRR exists at all. MIRR compounds money in at the reinvestment rate and money out at the finance rate, which is why it is usually lower than IRR. Nothing is uploaded; the solving happens in this tab.