Payback Period (Uneven cash flows) When the annual cash flows are unequal, the payback period is computed by adding the annual cash flows until such time as the original investment is recovered. If a fraction of a year is needed, it is assumed that cash flows occur evenly within each year. The steps for determining the payback period with uneven cash flows is as follows: 1. Add the annual cash flows to one another until the investment is recovered. 2. For each full year's worth of cash flows consumed, add that year to your calculation for total payback years. 3. If you arrive at a point where only part of the year's cash flows are needed, only add the fraction of the year's cash flows relevant to recovering the initial investment to the total payback years. 4. If the unrecovered investment is greater than the annual cash flow, the payback period is "1". If the unrecovered investment is less than the annual cash flow the time needed for payback is computed by dividing the unrecovered investment by the annual cash flow for than year. + Explanation of Time Needed for Payback with uneven cash flows Note: For each year in which the unrecovered investment meets or exceeds the annual cash flow, this is 1. For years in which the annual cash flow exceeds the unrecovered investment, this is the unrecovered investment divided by the annual cash flow for that year. If Then Unrecovered Investment Annual Cash Flow Time Needed for Payback Unrecovered Investment