NPV and IRR are two approaches used in capital budgeting decisions to evaluate given projects .All other things being equal, using internal rate of return (IRR) and net present value (NPV) measurements to evaluate projects often results in the same findings. However, there are a number of projects for which using IRR is not as effective as using NPV to discount cash flows. IRR's major limitation is also its greatest strength: it uses one single discount rate to evaluate every investment.
Oct 20 2015 10:55 PM
Although using one discount rate simplifies matters, there are a number of situations that cause problems for IRR. If an analyst is evaluating two projects, both of which share a common discount rate, predictable cash flows, equal risk, and a shorter time horizon, IRR will probably work. The catch is that discount rates usually change substantially over time. For example, think about using the rate of return on a T-bill in the last 20 years as a discount rate. One-year T-bills returned between 1% and 12% in the last 20 years, so clearly the discount rate is changing.