NPV measures value in currency
Net present value discounts forecast cash flows to today and subtracts the initial investment. It estimates how much value the modeled project adds above the selected discount rate. Because the result is expressed in money, NPV can compare the scale of value created by mutually exclusive investments.
IRR expresses a break-even discount rate
Internal rate of return is a rate at which the modeled NPV equals zero. It is intuitive as a percentage, but unusual cash-flow patterns can produce no solution or multiple solutions. IRR can also favor a smaller project with a high percentage return even when a larger project creates more total value.
Why NPV and IRR can disagree
Differences in project scale, timing and reinvestment assumptions can produce conflicting rankings. In a capital-constrained decision, organizations may also need to consider strategic fit, risk concentration, financing, liquidity and implementation capacity. Neither metric repairs weak forecasts.
A responsible decision sequence
Model cash flows transparently, choose and document a discount rate, review NPV, inspect possible IRR solutions, test sensitivity and challenge the operating assumptions. Use the result as decision evidence rather than as an automatic approval rule.
Educational limitation: this guide and calculator do not provide investment, accounting, tax or financial advice. Material decisions require verified data and qualified review.