What is Net Present Value (NPV)?
Net Present Value (NPV) represents the difference between the present value of future cash inflows and the present value of cash outflows over a given time horizon.
NPV is the foundational metric of modern corporate finance, actuarial science, and investment appraisal because it directly implements the Time Value of Money (TVM): a dollar received today is inherently worth more than a dollar received tomorrow due to its capacity to earn interest, combined with the eroding impact of inflation.
The Universal Mathematical Formula
NPV = ∑t=1n [ Ct / (1 + r)t ] − C0
Formula Variables Explained
| Variable | Name | Role in Formula |
|---|---|---|
| Ct | Net Cash Flow in Period t | The expected nominal dollar amount generated or disbursed in year t. |
| r | Discount Rate | The opportunity cost of capital, hurdle rate, or interest rate used to discount future money back to today. |
| t | Time Period | The specific year or time interval when the cash flow occurs (from 1 to n). |
| C0 | Initial Cash Outlay | The upfront cash spent at time zero to initiate the project or the buyout offer under consideration. |
| n | Total Duration | The total lifetime or number of periods in the investment horizon. |
Why NPV is Superior to Alternative Financial Metrics
- Versus Payback Period: The payback method completely ignores cash flows received after the breakeven date and fails to account for the time value of money.
- Versus Internal Rate of Return (IRR): IRR assumes cash flows are reinvested at the internal rate of return rather than the true cost of capital, creating distorted rankings for mutually exclusive projects.
- Versus Simple Accounting Rate of Return: Accounting metrics use net income rather than pure liquidity and cash flows.