The Net Present Value (NPV) method is a financial technique used to assess the profitability of an investment or project by comparing the present value of future cash inflows to the initial investment. The formula for NPV is:

Where:

1. R_t represents the net cash inflows expected in the future.
2. i is the discount rate, reflecting money's risk and time value.
3. t is the time period when the cash flow occurs.
4. C_0 is the initial investment or cost required for the project.

This formula sums the present value of all future cash inflows and subtracts the initial investment, yielding the NPV, which can be positive, zero, or negative. A positive NPV indicates profitability, while a negative NPV suggests the investment may not be financially viable.

When calculating NPV, it's essential to remember that the process of discounting cash flows is straightforward once the cash flows and discount rate are known. However, the real challenge lies in accurately estimating those cash flows and the appropriate discount rate. As these are only estimates, the actual NPV may vary, emphasizing the importance of making reliable projections.