DCF step by step: forecast, discount, and value safely

TL;DR

• Build free cash flow first, not a narrative about growth.
• Pick a discount rate that reflects business risk and capital structure, not the return you want.
• Terminal value often dominates the result, so test sensitivity before trusting the output.

A discounted cash flow model translates expected cash generation into a present value. It does not produce a true price for a stock, but a conditional estimate based on explicit assumptions. Corporate Finance Institute describes DCF as an analysis method used to value investments by discounting estimated future cash flows across a wide range of assets as long as future cash flows can be estimated.

This walkthrough keeps the process practical and deliberately avoids a valuation recommendation. The goal is to learn the method, not to reach a buy-or-sell conclusion about any specific company.

What a DCF actually values

In most equity work, the standard version of the model values the operating business first. That result is enterprise value: the combined value of debt and equity supported by the business. To move from enterprise value to equity value, you then adjust for non-operating items such as net debt and other claimholders. For context on how these claims are structured, see our guide to how to read a balance sheet.

This separation matters because it keeps the forecast focused on operating performance. Cash flow from operations, capital spending, working-capital needs, and investment returns are business questions. Debt repayments, interest, and dividend policy are financing decisions layered on top.

Investopedia defines DCF as a valuation method that estimates the value of an investment based on expected future cash flows, discounted back to today. The phrase “discounted back to today” is the key point: a dollar far in the future is not worth a dollar today unless risk and opportunity cost have already been accounted for.

Step 1: forecast free cash flow

The core cash flow in a standard DCF is unlevered free cash flow, sometimes called free cash flow to the firm. A common formula is:

FCF = NOPAT + D&A - CapEx - Increase in working capital

Where NOPAT is net operating profit after tax, D&A is depreciation and amortization, and CapEx is capital expenditure. Another equivalent view is:

FCF = Operating cash flow - CapEx

Either framing can work, but the first one is usually more transparent in a forecast because it separates operating profitability from reinvestment.

A practical approach is to forecast the drivers separately: revenue, operating margin, tax rate, depreciation relative to assets, capital intensity, and working-capital efficiency. Forecasting those line items is slower than projecting a single cash-flow margin, but it exposes where the value is really coming from.

For a simple educational case, assume a company has the following profile over five years:

• Year 1 revenue: $1,000 million
• Revenue growth: 8% per year
• NOPAT margin: 10%
• D&A: 4% of revenue
• CapEx: 6% of revenue
• Working-capital increase: 1% of revenue each year

That implies free cash flow grows as the business scales, while reinvestment rises with revenue. In practice, margins and reinvestment needs do not move in straight lines, so a real model should allow for variation by year.

Step 2: choose the discount rate

The discount rate should reflect the risk of the cash flows being valued. For an unlevered DCF of operating cash flows, the standard discount rate is weighted average cost of capital, or WACC. To see how these components come together in a real-world scenario, check our step-by-step WACC calculation guide.

As described on Aswath Damodaran’s valuation input materials, WACC is a weighted average of the cost of equity and the after-tax cost of debt. The cost of equity is often estimated with the capital asset pricing model, or CAPM:

Cost of equity = Risk-free rate + Beta x Equity risk premium

A simplified WACC for a company with only common equity and debt is:

WACC = (E / (D+E)) x Cost of equity + (D / (D+E)) x Cost of debt x (1 - Tax rate)

Capital weights should be based on market values, not book values, whenever practicable.

Investopedia explains that WACC represents the average rate a company expects to pay to finance its assets, and that it reflects the proportional mix of equity and debt financing. It is not a safety margin or a target return; it is a hurdle tied to how the company is financed and how risky its cash flows are.

Step 3: calculate terminal value

Most DCF models do not forecast cash flows forever. Instead, they forecast a limited explicit period, such as five or ten years, and then estimate terminal value to capture the remaining value beyond that horizon.

There are two common methods. The first is the perpetuity-growth method. For an unlevered DCF, one version is:

Terminal value = Final-year FCF x (1 + g) / (WACC - g)

Where g is the perpetual growth rate. The second is the exit-multiple method, which values the terminal year using a market multiple such as EV/EBITDA.

Wall Street Prep notes that terminal value can represent a very large share of total DCF value, which makes the valuation highly sensitive to small changes in the discount rate, growth rate, or terminal-year cash flow. A model that looks precise can still be highly uncertain if the terminal value dominates the result.

As an educational rule of thumb, the perpetuity growth rate should stay below the long-term growth rate of the economy.

Step 4: discount each cash flow to present value

Once forecast cash flows and terminal value exist, they must be brought back to today. For a standard DCF, each cash flow is divided by (1 + WACC)^t, where t is the number of years from the valuation date.

If a company has a five-year explicit forecast and then terminal value, the enterprise value calculation can be written as:

EV = Sum of PV of forecast FCFs + PV of terminal value

Cash flows received sooner are worth more than cash flows received later, even before considering risk. Discounting is the mathematical expression of that tradeoff.

Step 5: move from enterprise value to equity value

Enterprise value is the value of the operating business. To get to equity value, you need a bridge that reflects the claims on that business. A standard bridge is:

Equity value = Enterprise value - Debt + Cash Understanding the bridge between these two values is critical; read more in our breakdown of enterprise value vs equity value.

This captures the main idea: equity holders sit behind creditors and other senior claimholders. In practice, diluted shares should reflect outstanding equity, options, and other convertible instruments that may create new shares.

Step 6: test sensitivity and explain uncertainty

A DCF should never be presented as one clean number. It is a scenario tool. Sensitivity analysis shows how the result changes when key assumptions move. Common dimensions include:

• WACC
• Perpetuity growth rate
• Revenue growth
• Operating margin

A two-way sensitivity table around WACC and terminal growth is a useful starting point. It shows how fragile or robust the value is across a range of plausible assumptions.

Uncertainty should be explained explicitly. Typical sources include:

• Forecast error in revenue and margins
• Cyclicality or customer concentration
• Changing competitive dynamics
• Shifts in interest rates or tax policy

This is also where editorial caution matters. An educational DCF should not claim that a result is fair, cheap, or expensive. It should show how value depends on assumptions and where the model is weakest.

An illustrative example

To keep this concrete, consider an educational example with the following inputs:

• Five-year forecast horizon
• WACC: 9%
• Terminal growth rate: 3%
• Year 5 FCF: $80 million

The perpetuity-growth terminal value at the end of Year 5 would be:

TV5 = 80 x (1 + 0.03) / (0.09 - 0.03) = $1,373 million

That amount is a future value as of Year 5. To value it today, discount it back at WACC:

PV of TV = 1,373 / (1.09)^5 = $892 million

If the present value of the five-year forecast cash flows is $230 million, then the implied enterprise value is:

EV = $230 million + $892 million = $1,122 million

Now adjust to equity value. Suppose debt is $400 million and cash is $80 million:

Equity value = 1,122 - 400 + 80 = $802 million

This does not make the stock a buy or a sell. It makes the assumptions visible. Move WACC to 10% and terminal growth to 2%, and the present value of terminal value drops materially. That is exactly how the framework should be used: to understand what has to be true for a given valuation to hold.

Common errors and fixes

Frequently asked questions (FAQ)

What is the main purpose of a DCF?

The purpose of a DCF is to translate expected future cash flows into a present value under stated assumptions. It is a framework for disciplined thinking about value creation, not a machine for producing one correct number.

What cash flow should I use in a standard DCF?

For an enterprise DCF, the standard choice is unlevered free cash flow, also called free cash flow to the firm. This reflects operating performance before financing decisions, which keeps the valuation focused on the business itself.

Is terminal value optional?

It is theoretically optional if you forecast cash flows far enough, but in practice most models use an explicit forecast period and then add terminal value because far-out forecasts become unreliable. The important step is to test how sensitive the result is to terminal assumptions.

Why not use a high perpetuity growth rate to be conservative on discount rate?

That mixes two separate issues. A lower WACC raises value, while a higher terminal growth rate also raises value. Combining them to offset each other produces a misleading middle ground. Each input should be chosen on its own merits.

How many years should I forecast?

There is no universal rule. Many practitioners use five or ten years, but the right horizon is the period during which the company’s competitive position and reinvestment needs are meaningfully forecastable. After that, terminal value should capture the rest.

Can a DCF prove that a stock is cheap or expensive?

No. A DCF shows what the stock implies under the model’s assumptions. That is useful for scenario analysis and for comparing assumptions across companies, but it should not be framed as proof that a market price is wrong.

Sources

• Corporate Finance Institute — overview of the DCF formula, components, and terminal value concepts.
• Aswath Damodaran valuation inputs — discussion of WACC, capital structure, and valuation inputs.
• Wall Street Prep — terminal value methods, formulas, and sensitivity considerations.
• Investopedia on DCF — plain-English definition and use of discounted cash flow analysis.
• Investopedia on WACC — explanation of weighted average cost of capital and financing mix.