How to Calculate IRR in Excel Using the IRR function in Excel makes calculating the IRR easy. Excel does all the necessary work for you, arriving at the discount rate you are seeking to find.

The Excel IRR function can help you accomplish this task much easier. One of the disadvantages of using IRR is that all cash flows are assumed to be reinvested at the same discount rate ...

In most cases, investors use an IRR calculator or an Excel spreadsheet, which has a built-in function to determine a project's IRR. When calculating IRR, you're solving for an NPV of zero.