A discounted cash flow model, often abbreviated DCF, is a valuation technique that estimates the value of an investment, project, or entire business by discounting its expected future cash flows back to their equivalent value today, reflecting the time value of money. The underlying principle is simple: a dollar received further in the future is worth less than a dollar received today, both because of the opportunity to invest money sooner rather than later and because of the uncertainty inherent in any cash flow that has not yet actually arrived.
How a discounted cash flow model is built
Building a DCF model starts with projecting the expected future cash flows an investment or business is likely to generate over some forecast period, then discounting each of those projected cash flows back to the present using a chosen discount rate, typically the investor's or company's cost of capital. Summing all of those discounted amounts produces the model's estimate of present value, which can then be compared against an investment's actual cost or current market price to judge whether it looks attractively priced.
Net present value and internal rate of return
Two of the most common applications of the discounted cash flow model are net present value, which subtracts the initial investment cost from the present value of projected future cash flows to show the dollar value an investment is expected to create, and internal rate of return, which instead solves for the specific discount rate that makes an investment's net present value exactly equal to zero, giving a single percentage figure that can be compared against a required hurdle rate.
Why the discount rate choice matters so much
A discounted cash flow model's results are extremely sensitive to the discount rate chosen, since cash flows further in the future are discounted more heavily at higher rates, meaning even a modest change in the assumed rate can produce a dramatically different valuation, particularly for investments with cash flows weighted heavily toward distant future years. This sensitivity is one of the most important limitations analysts keep in mind, often testing a range of discount rates and growth assumptions, called sensitivity analysis, rather than relying on a single point estimate from one specific set of assumptions.
Why DCF models are widely used despite their limitations
Discounted cash flow models require numerous forecasts and assumptions about future performance that are inherently uncertain, which means the model's output is only as reliable as the inputs feeding into it, leading to the well-known observation that a DCF model can be used to justify almost any valuation depending on how aggressively its inputs are chosen. Despite this, the discounted cash flow model remains one of the most widely used valuation tools in corporate finance and investment analysis, precisely because it forces an explicit, transparent set of assumptions about future performance, rather than relying purely on comparisons to how similar investments happen to be priced in the market today.
A simple worked example
An investment expected to generate $100,000 per year for five years, discounted at a 10% rate, has a present value of roughly $379,000, meaningfully less than the simple $500,000 sum of the undiscounted cash flows, illustrating how significantly discounting reduces the value assigned to cash received further in the future. Raising the discount rate to 15% would lower that present value further, to roughly $335,000, showing just how sensitive the model’s output is to the specific rate chosen.