How to Build a DCF Model: A Complete Beginner's Guide

Imagine you could know, with certainty, every cash flow a business would ever generate — every pound of profit, every investment required, every sale and every cost, all the way to the end of time. If you knew all of that, working out what the business is worth today would be trivial: you would simply add up all those future cash flows.

The problem is that a pound received in ten years is not worth the same as a pound received today. You could invest today’s pound and it would grow. And the further into the future a cash flow lies, the more uncertain it is — more things can go wrong. So future cash flows need to be discounted: shrunk back to their equivalent value in today’s terms.

This is the entire logic of the Discounted Cash Flow model.

The DCF is the foundational valuation tool across investment banking, private equity, equity research, and corporate finance. Understanding how to build one is not just a technical skill — it forces you to think rigorously about how a business creates value and what assumptions actually drive that value. By the end of this guide you will have built a complete, working DCF for our case study company, WidgetCo Ltd.

Before you begin: This post assumes you are comfortable with the concept of Free Cash Flow. If you have not read the FCF guide yet, start there first — the FCF calculation is the essential input to everything that follows.

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The Core Idea in One Sentence

A DCF values a business by projecting its future free cash flows, discounting each one back to today using a rate that reflects risk and the time value of money, and then summing the results.

Formally:

Enterprise Value = Σ [FCFt / (1 + WACC)^t]  +  Terminal Value / (1 + WACC)^n

Where:

• FCFt = Free Cash Flow in year t
• WACC = Weighted Average Cost of Capital (the discount rate)
• n = length of the explicit forecast period
• Terminal Value = present value of all cash flows beyond year n

There are three key inputs to get right: the FCF projections, the discount rate, and the terminal value. Let us work through each.

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Step 1: Projecting Free Cash Flows

The most important — and most subjective — part of any DCF is the FCF forecast. No amount of mathematical precision in your discount factor will compensate for a poorly thought-through projection.

For a beginner DCF, use a 5-year explicit forecast period. This is standard in most coursework, investment banking models, and equity research. The further out you project, the less reliable the numbers become, which is why anything beyond year 5 is typically captured in the terminal value rather than projected explicitly.

Building the WidgetCo projections

We pick up directly from the FCF guide. WidgetCo generated £382k of FCF in Year 1. To project forward, we make the following assumptions (all entered in a dedicated Assumptions tab):

Assumption	Value	Rationale
Revenue growth rate (Yr 2–5)	8% per year	Consistent with market growth + pricing power
EBIT margin	15%	Stable; slightly improves with scale
D&A as % of revenue	4%	Broadly in line with asset intensity
CapEx as % of revenue	6%	Maintenance + modest growth investment
ΔNWC as % of revenue increment	10%	Working capital builds as business grows
Tax rate	25%	UK corporation tax

Applying these assumptions produces the following projections:

WidgetCo FCF Projections (£000s)

	Year 1	Year 2	Year 3	Year 4	Year 5
Revenue	5,000	5,400	5,832	6,298	6,802
EBIT (15%)	750	810	875	945	1,020
Tax (25%)	(188)	(203)	(219)	(236)	(255)
NOPAT	562	608	656	709	765
+ D&A (4%)	200	216	233	252	272
− CapEx (6%)	(300)	(324)	(350)	(378)	(408)
− ΔNWC (10% × ΔRev)	(80)	(40)	(43)	(47)	(50)
FCF	382	460	496	536	579

Notice that FCF grows at a slower pace than revenue. This reflects the capital required to support growth — every extra pound of revenue needs investment in assets and working capital.

Interview tip: If your model shows FCF growing faster than EBITDA year after year, something is wrong. Growing businesses consume cash; you should only see FCF growing faster than EBITDA in a business that is actively shrinking its capital base.

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Step 2: Choosing the Discount Rate (WACC)

WACC — the Weighted Average Cost of Capital — is the return that all capital providers collectively require from this business. It reflects two things: the time value of money (what you could earn on a risk-free investment) and the additional return required to compensate for the specific risks of this business.

The formula is:

WACC = (E/V × Re) + (D/V × Rd × (1 − Tax Rate))

Where:

• E/V = equity as a proportion of total capital (equity + debt)
• D/V = debt as a proportion of total capital
• Re = cost of equity
• Rd = pre-tax cost of debt (the company’s borrowing rate)

Estimating the cost of equity

The cost of equity (Re) is derived using the Capital Asset Pricing Model:

Re = Risk-Free Rate + Beta × Equity Risk Premium

• Risk-Free Rate: the yield on long-dated government bonds — typically 4–4.5% in the UK as of 2024
• Beta: a measure of how the company’s returns move relative to the market. A Beta of 1.0 = moves with the market. A Beta > 1.0 = more volatile than the market.
• Equity Risk Premium: the additional return equity investors demand over the risk-free rate — typically 5–7% for UK equities

For WidgetCo (a mid-size UK manufacturer with moderate cyclicality, Beta ≈ 0.9):

Re = 4.0% + 0.9 × 6.0% = 9.4%

Calculating WACC for WidgetCo

Parameter	Value
Cost of equity (Re)	9.4%
Cost of debt (Rd)	5.5%
Tax rate	25%
Equity / Total Capital	70%
Debt / Total Capital	30%
WACC	9.4% × 0.70 + 5.5% × 0.75 × 0.30 = 7.8%

Rounded to 8.0% for the base case (small rounding differences are normal and acceptable in student models).

For students working on private companies or case studies: You will not have a publicly traded Beta. Use the Beta of a comparable listed company (delever it for that company’s capital structure, then re-lever it for your target). This sounds complex but is a standard one-page calculation — look up “Hamada equation” when you are ready to go deeper.

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Step 3: Calculating Terminal Value

The explicit forecast period covers only 5 years. But WidgetCo is expected to keep operating and generating cash well beyond year 5. Terminal Value (TV) captures the present value of all those future cash flows in a single number.

There are two methods — and it is good practice to calculate both as a cross-check.

Method 1: Gordon Growth Model (Perpetuity Growth)

Terminal Value = FCF₅ × (1 + g) / (WACC − g)

g is the long-run sustainable growth rate — the rate at which FCF can grow indefinitely. For a UK-based company, use the long-run nominal GDP growth rate as a ceiling: roughly 2.0–2.5%. Using anything higher implies the company eventually becomes a meaningful fraction of the entire economy, which is implausible for almost any business.

TV = £579k × 1.025 / (0.08 − 0.025)
TV = £593k / 0.055
TV = £10,782k

Method 2: Exit Multiple (EV/EBITDA)

Terminal Value = EBITDA₅ × Exit Multiple

Year 5 EBITDA = EBIT₅ + D&A₅ = £1,020k + £272k = £1,292k

Using a 7× EV/EBITDA multiple (typical for a mid-market UK manufacturer):

TV = £1,292k × 7 = £9,044k

The two methods give £10,782k and £9,044k — a reasonable spread. We will use the Gordon Growth Model (£10,782k) for our base case and note the exit multiple as a sense-check.

Common mistake: Students often use terminal growth rates of 4–5%, especially when modelling fast-growing tech businesses. Resist this temptation. A perpetuity grows forever. In 30 years, a 5% perpetuity grows to more than four times its current size — for a business already generating £500k of FCF, that implies truly enormous scale. Keep g close to long-run GDP growth.

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Step 4: Discounting Everything Back to Present Value

With our FCF projections and terminal value in hand, we now discount each figure back to today using the discount factor 1 / (1 + WACC)^t.

Discounting the FCF projections (WACC = 8.0%)

	Year 1	Year 2	Year 3	Year 4	Year 5
FCF (£000)	382	460	496	536	579
Discount factor	0.926	0.857	0.794	0.735	0.681
PV of FCF (£000)	354	394	394	394	394
Sum of PV of FCFs					1,930

Discounting the Terminal Value

PV of Terminal Value = £10,782k × 0.681 = £7,342k

Enterprise Value

Enterprise Value = Sum of PV of FCFs + PV of Terminal Value
Enterprise Value = £1,930k + £7,342k = £9,272k

Bridge from Enterprise Value to Equity Value

From the balance sheet, WidgetCo has £800k of net debt (gross debt minus cash).

Equity Value = Enterprise Value − Net Debt
Equity Value = £9,272k − £800k = £8,472k

If WidgetCo has 1,000,000 shares in issue:

Implied share price = £8,472k / 1,000 = £8.47 per share

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Step 5: Build It in Excel — Clean Tab Structure

Here is the tab structure for a professional-quality beginner DCF. Keep each tab focused on one job.

Tab 1: Assumptions All hardcoded inputs go here, in blue font. Nothing else. Group them logically:

• Operating assumptions: growth rate, margins, D&A %, CapEx %, NWC %
• Capital structure: cost of equity, cost of debt, D/E ratio, tax rate
• Valuation: terminal growth rate, exit multiple, net debt, shares in issue

Tab 2: FCF Projections Drive all P&L and FCF lines from Assumptions. Year headers across columns (Year 0 as base, Year 1–5 forecast). Build the full FCF bridge: Revenue → EBIT → NOPAT → +D&A → −CapEx → −ΔNWC → FCF.

Tab 3: DCF Valuation

• Row 1: FCF row (linked from Tab 2)
• Row 2: Discount period (1, 2, 3, 4, 5)
• Row 3: Discount factor: =1/(1+WACC)^period
• Row 4: PV of FCF: =FCF × discount factor
• Row 5: Sum of PV of FCFs
• Row 6: Terminal Value (Gordon Growth formula)
• Row 7: PV of Terminal Value
• Row 8: Enterprise Value = Row 5 + Row 7
• Row 9: Less: Net Debt (from Assumptions)
• Row 10: Equity Value
• Row 11: Shares in issue (from Assumptions)
• Row 12: Implied Share Price

Tab 4: Sensitivity Analysis Build a two-way data table (Excel’s What-If Analysis → Data Table) with:

• Rows: WACC ranging from 6% to 10% in 0.5% steps
• Columns: Terminal growth rate ranging from 1% to 3.5% in 0.5% steps
• Output: Implied share price

This single table is often more informative than the base case valuation itself.

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Interpreting Your DCF Output

A single-point DCF valuation is not the goal. The goal is to understand the range of plausible values and the sensitivity of that range to your key assumptions.

Once you have your sensitivity table, look for two things:

1. The spread. How wide is the range between your bear and bull cases? A wide range means the valuation is highly uncertain — either because the business is volatile, or because the terminal value assumptions dominate. For WidgetCo, the range across plausible WACC and growth rate combinations might be £6,000k–£11,000k: a wide spread that reflects the inherent uncertainty of any forward-looking model.

2. The terminal value dependency. Divide the PV of Terminal Value by the total Enterprise Value. In our WidgetCo model: £7,342k / £9,272k = 79%. This is typical. It means the majority of enterprise value comes from beyond year 5 — and therefore depends entirely on your terminal growth rate and WACC assumptions. Be transparent about this when presenting a DCF to anyone. The explicit forecast period gives structure; the terminal value is where the real valuation leverage lies.

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Three Mistakes That Trip Up Beginners

Using too high a terminal growth rate. The Gordon Growth formula is a perpetuity: at g = 5% and WACC = 8%, you are implying the business grows for ever at 5%. Run the numbers forward 50 years — the implied FCF becomes absurd. Anchor g to long-run nominal GDP growth.

Mixing nominal and real rates. Your FCF projections are in nominal terms (they include the effect of inflation). Your WACC should also be nominal. Do not use a real WACC with nominal cash flows, or vice versa.

Forgetting to subtract net debt. Enterprise Value is the total value of the business to all capital providers. Equity Value is what is left for shareholders after repaying debt. Always perform the bridge: Equity Value = Enterprise Value − Net Debt + Cash.

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Key Takeaways

• A DCF values a business by discounting its future free cash flows back to today.
• The three building blocks are: FCF projections, WACC, and Terminal Value.
• Terminal value typically represents 60–80% of enterprise value — which means your g and WACC assumptions are the most important numbers in the model.
• Always present a sensitivity table alongside your point estimate. A single number is an anchor; a range is an honest analysis.
• The model is only as good as your business understanding. Spend most of your preparation time on the assumptions, not the formulas.

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Previous in series → Free Cash Flow Explained: The Number Every Analyst Needs to Understand

Next in series → Scenario and Sensitivity Analysis: How to Stress-Test Any Financial Model

Going deeper → Monte Carlo DCF: Adding Probability to Your Valuation