XIRR

The XIRR function calculates the internal rate of return for a series of cash flows that occur at irregular intervals. Payments are expressed as negative values and income as positive values. If the first value is a cost or payment, it must be a negative value. Subsequent payments are discounted based on a 365-day year. To calculate the internal rate of return for a series of regular, periodic cash flows, use the IRR function. XIRR is related to the XNPV function. The rate returned by XIRR is the interest rate when XNPV = 0. The XIRR function uses iteration to arrive at a result. Starting with guess (which defaults to 0.1 if not provided) XIRR iterates through a calculation until the result is accurate to 0.000001 percent. If no result is found after 100 tries, XIRR returns the #NUM! error