The Excel NPER function is one of many Excel financial functions, and can be used to calculate the number of periods for a lump sum, annuity or annuity due to grow to a future value. In addition the function can also be used to calculate the number of periods it takes for a loan to be repaid.
The profitability index (PI) of a series of cash flows is found by calculating the present value of all the cash flows from a project (PV) and dividing the value by the initial investment (I). The profitability index is sometimes referred to as the value investment ratio.
The effective interest rate formula calculates the rate of interest for a year based on a nominal rate (i) compounded a number of times a year (m). The formula for annual interest rate is sometimes referred to as the annual equivalent rate formula or AER formula.