Walk Me Through a DCF – Step-by-Step Interview Answer
The 30-Second Answer
If you only have 30 seconds, say this: “A DCF values a company by projecting its unlevered free cash flows for 5–10 years, then calculating a terminal value to capture value beyond the projection period. You discount all cash flows back to present value using WACC, sum them up to get enterprise value, then subtract net debt to arrive at equity value and divide by shares outstanding to get price per share.”
That hits every key concept. Now let’s break it down.
Step 1: Project Free Cash Flows
Start by projecting the company’s unlevered free cash flow (UFCF) for the next 5–10 years. UFCF represents cash available to all capital providers — both debt and equity holders.
Build your projections from revenue growth assumptions down through margins, depreciation, capital expenditures, and changes in working capital. Base your assumptions on historical trends, management guidance, and industry benchmarks. Be ready to justify every assumption — interviewers will push back.
Step 2: Calculate WACC
WACC is the blended cost of capital that reflects the risk of the business. It’s used as the discount rate.
Where Re = cost of equity (from CAPM), Rd = cost of debt (pre-tax), E = market value of equity, D = market value of debt, V = E + D, and T = tax rate. Cost of equity uses CAPM: Risk-Free Rate + Beta × Equity Risk Premium. Typical WACC for a mid-cap US company ranges from 8–12%.
| WACC Component | What It Represents | Typical Range |
|---|---|---|
| Risk-Free Rate | 10-year US Treasury yield | 3.5–5.0% |
| Equity Risk Premium | Expected market return above risk-free | 5.0–7.0% |
| Beta | Stock’s sensitivity to market movements | 0.8–1.5 for most companies |
| Cost of Debt | Average interest rate on borrowings | 4.0–8.0% |
| Tax Rate | Effective corporate tax rate | 21–25% |
Step 3: Calculate Terminal Value
The terminal value captures all cash flows beyond the projection period. It often represents 60–80% of total enterprise value, which is why it’s so important to get right. Two methods:
Gordon Growth Method (Perpetuity Growth)
Where g is the perpetual growth rate (typically 2–3%, in line with long-term GDP or inflation). This method assumes the business grows at a constant rate forever.
Exit Multiple Method
Use the EV/EBITDA multiple from comparable companies. This is often preferred in practice because it’s grounded in market data. Use both methods as a sanity check against each other.
Step 4: Discount to Present Value
Discount each year’s free cash flow and the terminal value back to today using WACC:
Sum all present values to get enterprise value. Use mid-year convention if cash flows arrive evenly throughout each year rather than at year-end (most analysts do).
Step 5: Bridge to Equity Value
Subtract net debt (total debt minus cash) from enterprise value to get equity value. Divide by diluted shares outstanding to get implied share price. Compare this to the current stock price to assess whether the company is undervalued or overvalued.
Common Interview Follow-Ups
What’s the most important assumption in a DCF?
The terminal value assumptions — either the perpetual growth rate or the exit multiple. Since terminal value is typically 60–80% of the total enterprise value, small changes in these assumptions move the valuation significantly. After that, the discount rate (WACC) and revenue growth rate are the next most impactful.
When would a DCF give you a misleading valuation?
When cash flows are unpredictable (early-stage startups, cyclical companies in a downturn), when the company doesn’t generate positive FCF, or when capital structure is rapidly changing. DCFs also struggle with companies going through major transitions like restructurings or pivots.
Key Takeaways
- A DCF projects unlevered free cash flows, discounts them using WACC, and bridges to equity value — memorize this flow cold.
- Terminal value is the single biggest value driver — understand both the Gordon Growth and Exit Multiple methods.
- WACC blends the cost of equity (CAPM) and after-tax cost of debt — know how to calculate each component.
- Always run sensitivity analysis on WACC and terminal assumptions to show a range of values.
- Practice delivering the full walkthrough in under 2 minutes — conciseness wins in interviews.
Frequently Asked Questions
How long should my DCF walkthrough be in an interview?
Aim for 60–90 seconds for the initial walkthrough. The interviewer will ask follow-ups if they want more detail. Start with the high-level framework, then dive into specifics as prompted. Don’t front-load every detail — let the conversation flow naturally.
Should I use the Gordon Growth or Exit Multiple method for terminal value?
Use both and cross-check. In practice, the exit multiple method is more common because it’s grounded in observable market data. The Gordon Growth method is a good theoretical check. If they diverge significantly, investigate why — it usually means your growth or multiple assumptions are off.
What perpetual growth rate should I use?
Typically 2–3% for mature companies in developed markets. This should approximate long-term GDP growth or inflation. Never use a growth rate higher than WACC — it would imply infinite value, which is mathematically and economically impossible.
How is a DCF different from an LBO analysis?
A DCF calculates intrinsic value based on cash flows to all stakeholders. An LBO analysis calculates the maximum price a financial sponsor can pay given leverage constraints and target returns. DCFs use WACC as the discount rate; LBOs focus on equity IRR (typically 20–25%).
Do I need to build a DCF model for the interview?
Rarely during a verbal interview — but you should be able to walk through every step conceptually. Some firms give separate modeling tests where you build a DCF in Excel. Even for verbal interviews, having built one from scratch will deepen your understanding significantly.