How to Build a DCF Model: Step-by-Step Discounted Cash Flow Valuation

A DCF model estimates the intrinsic value of a business by calculating the present value of all future cash flows the business is expected to generate. The logic is fundamental: a business is worth the cash it will produce over its lifetime, discounted back to today at a rate that reflects the risk of receiving those cash flows. If the present value of future cash flows is $50 per share and the stock trades at $35, the DCF suggests the stock is undervalued. If it trades at $70, the DCF suggests it is overvalued. What a DCF does well: it forces you to think carefully about the fundamental drivers of value — revenue growth, margins, capital requirements, and risk. It is based on cash flows (which are harder to manipulate than earnings), and it provides a framework for disagreement (if two analysts get different values, they can compare their assumptions). What a DCF does NOT do well: it does not tell you when the market will reflect intrinsic value (a stock can stay undervalued for years), and it is extraordinarily sensitive to assumptions about growth and the discount rate. Small changes in these inputs produce large changes in the output — which is why sensitivity analysis is not optional, it is a core part of every DCF.

Free Cash Flow to the Firm is the cash available to all capital providers (debt and equity holders) after the company has paid operating expenses, taxes, and reinvested in the business. The formula: FCFF = EBIT × (1 - Tax Rate) + Depreciation & Amortization - Capital Expenditures - Change in Net Working Capital. Start by projecting revenue for the next 5-10 years (the explicit forecast period). Base this on historical growth rates, industry trends, management guidance, and your own analysis. Then project EBIT margins — will margins expand (from operating leverage or pricing power), stay flat, or compress (from competition or rising costs)? Apply the tax rate to get NOPAT (Net Operating Profit After Tax). Add back depreciation and amortization (non-cash charges). Subtract capital expenditures (the cash spent on maintaining and growing the asset base). Subtract increases in net working capital (the cash tied up in accounts receivable and inventory, minus the financing provided by accounts payable). Each of these line items requires a thoughtful assumption. Do not just grow every line at the revenue growth rate — capex may need to increase faster during an expansion phase, working capital needs may change as the business model evolves, and margins may shift as the company scales. The quality of your FCFF projections depends entirely on the quality of your assumptions, which should be grounded in the company's historical patterns and forward-looking analysis.

After the explicit forecast period (say, year 5 or year 10), the company does not stop generating cash — it continues indefinitely. Terminal value captures the value of all cash flows beyond the explicit forecast period, and it typically represents 60-80% of total enterprise value in a DCF. This is both the most important and the most uncertain part of the model. There are two common methods. Perpetuity Growth Method: Terminal Value = FCFF in final year × (1 + g) / (WACC - g), where g is the long-term perpetual growth rate. This assumes FCFF grows at a constant rate forever. The growth rate should be modest — typically 2-3% for mature companies in developed economies, roughly in line with long-term nominal GDP growth. Using a terminal growth rate above 4-5% implies the company will grow faster than the economy forever, which is unrealistic for almost any company. Exit Multiple Method: Terminal Value = EBITDA in final year × EV/EBITDA multiple. This values the business at the end of the forecast period as if it were being sold at a market-comparable multiple. The multiple should be based on peer company valuations — but be careful about using today's multiples for a point 5-10 years in the future, as market conditions may be very different. Best practice is to use both methods and compare the results. If they are in a similar range, that increases confidence. If they diverge significantly, investigate which assumptions are driving the difference.

All projected cash flows (both the explicit forecast FCFF and the terminal value) must be discounted to the present at the Weighted Average Cost of Capital (WACC). WACC represents the blended return required by all capital providers (debt and equity), weighted by their proportion of total capital. WACC = (E/V) × Re + (D/V) × Rd × (1-T). Where Re = cost of equity (typically from CAPM: Rf + β × Market Risk Premium), Rd = cost of debt (YTM on the company's bonds or borrowing rate), T = marginal tax rate, E = market value of equity, D = market value of debt, V = E + D. The present value of each year's FCFF is: FCFF / (1 + WACC)^n, where n is the number of years into the future. The terminal value is also discounted back from the final year of the explicit forecast: TV / (1 + WACC)^n. Sum all the discounted FCFF values plus the discounted terminal value. This sum is the Enterprise Value. WACC typically ranges from 7-12% for publicly traded US companies. A small change in WACC has a massive impact on the output because it compounds across every future year and amplifies through the terminal value calculation. A 1% increase in WACC can reduce the DCF value by 15-25%. This is why the sensitivity table (discussed below) always includes WACC as a variable.

The DCF produces an Enterprise Value (EV), which is the value of the entire business — owed to both debt holders and equity holders. To get to Equity Value (what shareholders own), you must subtract what is owed to other capital providers and add non-operating assets. Equity Value = Enterprise Value - Total Debt - Preferred Stock - Minority Interests + Cash and Cash Equivalents. Subtract debt because debt holders have a senior claim on the company's cash flows. Subtract preferred stock and minority interests for the same reason. Add cash because it is a non-operating asset that belongs to equity holders and could theoretically be distributed to them immediately. Per Share Value = Equity Value / Fully Diluted Shares Outstanding. Use fully diluted shares (which includes the dilutive effect of stock options, warrants, and convertible securities) rather than basic shares. The treasury stock method is the standard approach for calculating diluted shares from options and warrants. Compare your per share value to the current market price. If your value is higher, the DCF suggests the stock is undervalued. If lower, overvalued. But remember: your DCF is a model built on assumptions, not a guarantee. The market may know something you do not, your growth projections may be too optimistic, or your WACC may be too low. FinanceIQ can help you work through each step of a DCF valuation — input the projected cash flows and assumptions, and the app shows the discounting, terminal value calculation, and equity bridge with explanations at each stage. This guide is for educational purposes only and does not constitute financial or investment advice.

A DCF that presents a single point estimate without sensitivity analysis is incomplete and potentially misleading. The two variables that drive the most variation in DCF output are the terminal growth rate and the WACC (or equivalently, the terminal multiple if using the exit method). Build a two-way sensitivity table: put terminal growth rates across the top (e.g., 1.0%, 1.5%, 2.0%, 2.5%, 3.0%) and WACC down the side (e.g., 8.0%, 8.5%, 9.0%, 9.5%, 10.0%). Each cell shows the implied per share value under that combination of assumptions. If your base case is WACC = 9% and terminal growth = 2.5%, the table shows what happens if you are wrong. If the range of values in the table is $30-$80 and the stock trades at $50, the DCF is not particularly helpful — the stock is in the middle of a very wide range. If the range is $60-$120 and the stock trades at $45, the DCF more strongly suggests undervaluation because even the most conservative assumptions produce a value above the current price. A second useful sensitivity: revenue growth rate vs. operating margin. This shows how the value changes with different business performance outcomes, independent of the financial assumptions (WACC and terminal growth). Professional analysts routinely include both tables. They communicate not just what the model says, but how confident you should be in what it says.