What is discounted cash flow?
- Discounted cash flow (DCF) calculates the present value of an asset by discounting its future cash flows at a discount rate that reflects risk and time.
- The discount rate is the heart of DCF; small changes in it can swing the final value by thousands or millions.
- Terminal value often makes up 50% to 80% of a DCF valuation, so getting that assumption right is huge.
- DCF is only as good as your inputs. Garbage in, garbage out. Change one growth assumption and the answer changes a lot.
- You can use DCF to value stocks, projects, companies, or even real estate. It's the same math everywhere.
What is discounted cash flow?
Discounted cash flow (DCF) is a valuation method that estimates the present value of an investment by discounting future cash flows at a required return. It tells you what future money is worth today, so you can judge the price.
How does DCF work?
You start with future cash flows, the money you expect the asset to throw off each year. Then you apply a discount rate. That rate reflects the risk and the time value of money. The higher the risk, the higher the rate, and the lower the present value.
The DCF formula
The math is simple. Each future cash flow gets divided by (1 + discount rate) raised to the year number. Add them all up. That sum is the present value. $100 one year from now at a 10% discount rate is worth $90.91 today. Two years out? $82.64.
Terminal value: the big chunk
Most DCF models only forecast cash flows for 5 or 10 years. After that you need a terminal value, the worth of everything the business earns beyond the forecast. It often makes up 50% to 80% of the final number.
One way to get it is perpetual growth, which assumes cash flows keep rising at a steady fixed rate forever. Change that growth rate by just 1% and the answer can move by 20% or more, since this chunk dominates the value.
The other way is the exit multiple method. You assume the business is sold when the forecast ends, take its final-year EBITDA, and apply a market multiple, just as a traded peer carries. Bankers like it because it bakes real market prices into the number.
Why the discount rate matters
The discount rate is the return you demand for taking on the risk. For a company, it's usually the weighted average cost of capital (WACC). For a project, it might be your required return.
If you use 8% instead of 10%, the present value climbs noticeably. That's why two analysts can look at the same company and get wildly different values, even when their future cash flow forecasts are nearly identical.
The only edge: assumptions are everything
DCF is a mechanical tool. It takes your inputs and spits out a number. It is only as good as your guesses. Change the growth rate from 3% to 4% and you add millions. Move the discount rate from 9% to 11% and you can cut it in half.
So you must stress-test your assumptions and run a range of scenarios to see the spread of outcomes. The DCF doesn't give you the truth. It gives you a map of what your assumptions imply.
Worked example: a simple DCF
Say you expect a business to generate $1,000 in cash flow each year for the next 5 years, then you'll sell it for $5,000 at the end of year 5. Your discount rate is 10%.
Year 1: $1,000 / 1.1 = $909. Year 2: $1,000 / 1.21 = $826. Year 3: $1,000 / 1.331 = $751. Year 4: $1,000 / 1.4641 = $683. Year 5: $1,000 / 1.61051 = $621.
Plus the terminal sale of $5,000 / 1.61 = $3,105. Sum them: $909 + $826 + $751 + $683 + $621 + $3,105 = $6,895. That is the intrinsic value. If the price sits below it, you buy. If above, you walk away.
Where DCF falls short
Forecasting is hard. Nobody knows next year's cash flows, let alone 10 years out. That's why DCF works best for stable businesses like utilities. For startups or fast-changing industries, the uncertainty is huge.
DCF also ignores things like brand strength or management quality unless you bake them into the numbers, so qualitative judgment has to fill that gap on its own for non-financial value drivers.
Net present value and DCF are close cousins
The sum of all your discounted future cash flows is called net present value, or NPV. The only real difference sits up front. A DCF stops at the present-value sum, while NPV subtracts the initial investment you must lay out to buy the asset.
That makes NPV the natural yes or no gauge for a project. A positive NPV means the future value beats your cost. A negative one means you pay more today than the discounted future is worth, so the project quietly bleeds value.
The cash flows you actually discount
For a whole company, the number you discount is free cash flow, the money left after operating costs and capital spending. Valued for all investors, that is unlevered free cash flow, before debt costs. For equity holders alone, you discount free cash flow to equity instead.
Bonds get discounted on their interest payments. Real estate on its rental income. In every case the move is the same: estimate the cash that reaches a given owner, discount it at that owner's required rate, and the math hands back the value.
Once you value the whole company, the equity value bridge converts the result into what each share is worth. Add non-operating assets like cash, subtract net debt, then divide by the shares outstanding. That per-share number is the price you compare against the market.