Behind the abbreviation DCF sits a simple idea: a company is worth the sum of all the cash flows it will generate in the future – discounted to today. A euro tomorrow is worth less than a euro today, and discounting is exactly what the DCF does systematically.

Unlike market-based methods such as trading comps, the DCF does not derive value from the market but from the company itself. That makes it an intrinsic valuation – and at the same time sensitive to its assumptions. Understand the logic and you can both build it and explain it confidently in an interview.

In this guide you get the five steps of the DCF, the formulas for WACC and terminal value, a simplified worked example, a sensitivity view, plus the typical mistakes and interview questions. The classic „walk me through a DCF“ will no longer be a problem.

Why the DCF model matters

The DCF is the backbone of intrinsic valuation. In practice, every analyst, every private equity investor and every equity analyst uses it to derive a grounded value independent of current market sentiment. If you want to understand why a company is worth a certain price, you cannot avoid the DCF.

In the investment banking interview it is the star of the technicals. The question „walk me through a DCF“ is one of the most frequently asked of all. It tests not just whether you know the steps, but whether you have grasped the logic behind them – because every answer invites follow-ups.

The DCF is especially rewarding here: it can be fully prepared. Whoever can cleanly explain the five steps, WACC and terminal value immediately stands out from candidates who only memorised keywords.

Fundamentals: the idea behind the DCF

The DCF rests on the time value of money: money you receive in the future is worth less today – because of inflation, foregone returns and risk. To make future cash flows comparable, you discount them at a discount rate to their present value.

To value an entire company you use unlevered free cash flow. This is the cash flow that accrues to all capital providers – debt and equity – and is therefore independent of the financing structure. The matching discount rate is the WACC, the weighted average cost of capital.

The building blocks of free cash flow

Unlevered free cash flow is made up of several building blocks. The starting point is operating profit (EBIT), from which a notional tax is deducted – as if the company were unlevered. You then add back depreciation and amortisation, because they are non-cash. From that you subtract capex and the change in working capital, since both tie up real money. What remains is the cash flow freely available to all capital providers.

The five steps of the DCF

A DCF always follows the same logic. These are the five steps you should be able to explain fluently in an interview:

WACC and terminal value in detail

The WACC

The WACC (weighted average cost of capital) weights the cost of equity and debt by their share of the financing. Simplified, the formula is: WACC = equity weight × cost of equity + debt weight × cost of debt × (1 − tax rate). The tax benefit on debt (tax shield) lowers the effective cost of debt.

The cost of equity is usually derived via the Capital Asset Pricing Model (CAPM): risk-free rate plus beta times the market risk premium. Beta measures how much the stock moves relative to the overall market. Remember: a higher WACC lowers the present value of the cash flows and therefore the company value.

The terminal value

The terminal value captures the value of all cash flows after the explicit forecast period. There are two common methods:

Simplified worked example

The following figures are a simplified illustrative example of the method – not real market values.

Projected free cash flows

In this example the cash flows grow from 100 to EUR 140m. You discount each of these values back to today at the WACC of 9 % – so a cash flow in year 5 is discounted more heavily than one in year 1. For the value after year 5 you need the terminal value.

Take a company with an unlevered free cash flow of EUR 140m in the final forecast year, a WACC of 9 % and a perpetual growth rate g of 2 %. The terminal value under the Gordon growth method works out as:

You discount this terminal value, like the individual annual cash flows, back to today at the WACC. The sum of the discounted annual cash flows and the discounted terminal value gives Enterprise Value. Subtract net debt and you get Equity Value and – divided by the share count – value per share.

Sensitivity analysis

A DCF is only as good as its assumptions. Because small changes in WACC and growth rate move the value strongly, you never present the result as a single number but as a range. The sensitivity analysis varies the two most important levers – typically WACC and g – and displays the resulting values in a matrix.

This lets the reader see at once how robust the value is. In an interview, mentioning a sensitivity analysis signals that you understand the limits of the model – a strong sign of maturity.

When the DCF fits

The DCF works best for companies with stable, predictable cash flows – mature firms with established business models. Here assumptions can be made robustly and the result is meaningful.

It gets harder for young growth companies without positive cash flows, for highly cyclical businesses or where there is high uncertainty about the future. Then the assumptions dominate the result, and market-based methods often give a more robust picture. That is why the DCF is always combined with multiples in practice.

Expert tips for the interview

• Explain in five steps. Start with a clear roadmap rather than jumping into detail. Structure signals understanding.
• Use unlevered cash flows and WACC. And know why: this matches the cash flow to the discount rate and gives you Enterprise Value.
• Know the WACC effect. Raise the WACC and the value falls. This follow-up comes up almost every time.
• Frame the terminal value. Point out that it usually makes up the largest share of value – that shows real understanding.
• Mention sensitivity. No value is a single number. Saying so makes you sound like an analyst.

Common mistakes

• Using levered instead of unlevered cash flows. Then the cash flow does not match the WACC and the valuation becomes inconsistent.
• Setting too high a perpetual growth rate. A g above long-run economic growth is unrealistic and inflates the terminal value.
• Forgetting net debt. Without the bridge you confuse Enterprise Value and Equity Value.
• Not discounting the terminal value. It too must be discounted back to today.
• Not questioning assumptions. Garbage in, garbage out – realistic inputs matter more than a complex model.

Best practices

Here is how to build a clean, credible DCF:

1. Build the forecast on transparent, justified assumptions – not on wishful numbers.
2. Keep the cash flow definition and discount rate consistent (unlevered with WACC).
3. Sanity-check the terminal value with both methods (Gordon growth and exit multiple).
4. Always add a sensitivity analysis for WACC and growth rate.
5. Compare the DCF result with market-based methods such as multiples instead of relying on a single number.

Comparison tables

DCF vs. multiples

Terminal value: Gordon growth vs. exit multiple

Both terminal-value methods are often used in parallel and checked against each other.

Pros and cons

Frequently asked questions

Conclusion

The DCF model values a company from within: as the present value of its future unlevered cash flows, discounted at the WACC. The five steps – project, determine the WACC, discount, terminal value, sum and bridge – form the frame, and the terminal value with its assumptions is the most sensitive lever.

Understand the logic properly and you not only build better models but also handle the most important technical question in the interview with confidence. That is exactly what you can prepare for.