Investment Analysis (NPV)
🏭 Industrial · Net present value, payback period, and profitability index
Engineering projects are not just technical decisions but economic ones too. To evaluate whether an investment is “good,” future cash flows need to be discounted to present value — because 100 units of money received in the future is worth less than 100 units today (the time value of money).
Net Present Value (NPV) is found by subtracting the initial investment from the sum of the present values of all future cash flows. If NPV > 0, the project delivers a return greater than the chosen discount rate, and the investment is economically acceptable.
How is the discount rate (r) chosen? This rate is usually made up of expected inflation + the risk-free rate of return + a risk premium specific to the project’s risk. In highly uncertain or high-inflation environments (e.g. emerging economies), this rate can reach high values like 20-30%.
Simple payback period is a cruder metric that ignores the time value of money, but it’s still widely used because it gives investors an intuitive answer to “how long until I get my money back.”
This tool's calculation logic has been checked against a hand-computed numerical verification test. Test source: src/lib/calc/npv.test.ts.
- [13] Blank, Leland and Tarquin, Anthony. Engineering Economy, 8 ed.. McGraw-Hill, 2018. ↗
Investment Analysis (NPV) — EngineersLab calc card
Formula: NPV = −I₀ + Σ CF/(1+r)ᵗ
Sources: [13] Engineering Economy
Tool version: 1.0.0 · Date:
Source URL: https://engineerslab.com.tr/en/araclar/npv
Results are for educational and preliminary-sizing purposes; final engineering design decisions must reference the relevant standards and a licensed engineer's approval.