DCF Valuation Made Simple
This conversation was generated using Cook'd AI's career assistant and reviewed by Fallon Han from our editorial team for accuracy.
I'm a final-year economics student in India targeting bulge-bracket investment banking, and I do not have visa sponsorship yet. Can you start from the DCF formula and unpack how the pieces fit together before we get into the common mistakes? I want to understand the full module, not just one calculation.
Absolutely. Think of DCF as a chain: forecast free cash flows, discount them back using WACC, then add terminal value, and finally move from enterprise value to equity value by subtracting net debt and other claims. In formula form, it is often written as Equity Value = Present Value of Forecast Cash Flows plus Present Value of Terminal Value, then adjust for net debt. The key idea is that each input changes the final equity value differently. Cash flows drive the explicit period value, WACC sets the discount rate, and terminal value usually dominates the result, so small changes there can move the valuation a lot.
Before we go deeper, why do we use WACC in the first place, and how should I think about it if I am explaining this in an interview for banking? I want a clean intuition, not just the formula.
Use WACC because DCF is valuing the business as a whole, not just equity. The company is funded by both debt and equity, so the discount rate should reflect the blended required return of all capital providers. In interview terms, you can say WACC is the opportunity cost of investing in the operating assets of the business. If WACC rises, present values fall, which reduces enterprise value and then equity value too. If the company has more debt, the WACC can fall because debt is cheaper than equity, but only up to the point where financial risk does not start pushing costs back up.
Got it. So if I change WACC, what happens to the equity value step by step? And how is that different from changing the cash flow forecast itself?
Changing WACC affects every discounted cash flow and the terminal value, so it usually has a broad valuation impact. Higher WACC means each future rupee is worth less today, so enterprise value drops, and after subtracting net debt, equity value drops too. Changing the cash flow forecast is different because it changes the numerator, not the discount rate. If you increase revenue growth or margins, free cash flow rises, so value rises even if WACC stays the same. In a clean interview answer, say WACC is the lens through which all value is viewed, while cash flow assumptions are the underlying business drivers.
Now I want to understand terminal value properly. In most DCFs it seems to dominate the answer. How do I explain what it is and why it matters so much?
Terminal value is the value of the business beyond the explicit forecast period. Since you cannot forecast every year forever in detail, you estimate the value of the remaining cash flows at the end of the model period using either a perpetuity growth method or an exit multiple method. It matters so much because the explicit forecast may cover only five years, while the terminal value captures everything after that, which is often the majority of enterprise value. If your terminal assumptions are aggressive, the valuation can look much higher even if the near-term forecasts are modest. That is why bankers always test whether terminal assumptions are realistic and consistent with the business and the economy.
If terminal value is so sensitive, what are the common errors I should avoid when building or explaining a DCF? I want the kinds of mistakes that actually show up in interviews or case work.
The most common errors are mixing up enterprise value and equity value, using inconsistent assumptions, and double counting items. For example, people sometimes forget to subtract net debt when moving from enterprise value to equity value, or they use EBIT-based cash flows but apply an equity discount rate instead of WACC. Another common mistake is letting terminal growth exceed long-term nominal GDP growth, which makes the model look unrealistic. Also watch for circular logic: if leverage changes, debt and interest can affect WACC and cash flows at the same time, so you need to be consistent. In interviews, a strong answer is to say you always check the bridge from operating assumptions to WACC, terminal value, and then to equity value to make sure the story still makes sense.