Method Two Let’s assume that we didn’t calculate the IRR of 57% as we did above and have no idea what the correct discount rate is. We can use Excel’s What-If calculator in this case.

Profit margins vary by industry and should only be compared to those of similar companies. You can use computer software, such as Microsoft Excel, to quickly calculate profit margins.

As a result, the forward P/E ratio can more accurately reflect a company's valuation vs. using the historical P/E ratio. Here are the steps to calculate forward P/E in Excel.