Part of the fundamental financial analysis of any company, investment security, or business project entails the computation of cash flows. This is typically done in a cash flow template Excel spreadsheet which is pre-built for the purpose. The reason for this is that this type of template is not a simple calculator you build on the fly with little effort. It requires a lot of thinking, organizing the spreadsheets and formulas, and some planning about how to model cash in and cash out for each potential investment. In other words, there is no cookie cutter approach because each potential investment has different profit and loss drivers.
One of the first things to consider is what kind of data you have to work with in your cash flow template Excel spreadsheet. Ideally, you’re looking for accurate monthly data including income statement items like revenue and operating expenses and balance sheet items like equipment purchases and cash from financing activities. If you have a longer time frame you can go with quarterly periods, but annual tends to be too long. After all, how can you predict what is going to happen beyond 5 years with any accuracy unless you’re valuing an annuity?
Next, how much detail do you need in your cash flow template Excel spreadsheet at the individual line item level? Is cash from financing sufficient or do you need equity financing, debt financing, interest earned, etc. Also how do you intend to handle depreciation and amortization, since these are non-cash items that are typically added back to the income statement entries when determining the cash effect.
Also, how long is your investment horizon? Is it really that important to you to project out to 30 years or is 3-5 years sufficient along with a terminal value that represents the expected NPV beyond 5 years? Usually this latter approach works best and looks the most credible to potential investors. There are numerous ways to calculate terminal value including multiples, current market values projected forward, and round guesstimates. Obviously these decisions are affected by your personal preference and the type of investment for which you’re calculating present value.
Finally, when applying discount factors, where do you intend to get your discount numbers? For a company with existing debt and equity capital you can calculate WACC and use that. For a startup company you need to figure out a risk-adjusted cost of capital that makes sense. Usually this is not just a risk-free rate which only the largest companies in the world have access to. It’s probably something higher.