Fair Value & DCF: What a Stock Is Really Worth
A stock’s price tells you what other people are paying for it right now – not what the company is worth. If you only watch the price, you end up buying dear when the mood is euphoric and selling cheap when it turns. The way out is an anchor of your own: intrinsic value, often called fair value. In this guide you’ll learn the most important method behind it – discounted cash flow (DCF) analysis – complete with a simplified worked example, the biggest pitfalls, and the reason a value range is more honest than any point estimate.
Intrinsic value: price is what you pay – value is what you get
The core idea goes back to Benjamin Graham and was made famous by Warren Buffett: a stock is a share in a business, and a business is worth all the cash it will generate for its owners over its remaining life – discounted back to today. The market price oscillates around that value, sometimes sitting above it for years, sometimes well below it.
From this follows the central question of all fundamental analysis: is the current price above or below intrinsic value? To answer it, you need a valuation method. The theoretically cleanest one is the DCF.
The DCF logic: discounting future free cash flows
DCF stands for “discounted cash flow”. The method answers one question: what are all of the company’s future free cash flows worth today?
You need three building blocks for that:
- Free cash flow (FCF): the money that is actually left over after all operating costs and investments. It is more honest than reported profit because it is much harder to dress up through accounting choices. You’ll find the exact definition of FCF in the glossary.
- Growth assumptions: how fast will FCF grow over the next few years – and at what rate after that, “forever” (the so-called terminal growth rate)?
- Discount rate: the interest rate you use to translate future payments into today’s money. It reflects your required return and the riskiness of the business – typically 8–10% for solid companies, more like 11–14% for risky ones.
Why discount at all?
€100 in five years is worth less than €100 today. First, you could invest the money today and earn a return on it; second, every future payment is uncertain. At a 9% discount rate, €100 that only arrives in five years is worth just about €65 today (100 ÷ 1.09⁵). The further away and the riskier a payment, the less it counts today – and that is exactly what the discount rate captures.
A simplified worked example
Take a fictional company with these assumptions:
- Most recent free cash flow: €100 million
- Growth: 8% per year for the next five years
- Terminal growth after that: 2% (roughly the level of inflation)
- Discount rate: 9%
- No net debt, 100 million shares outstanding
Step 1: project FCF for years 1–5 and discount each year individually.
| Year | FCF (€ million) | Discount factor (9%) | Present value (€ million) |
|---|---|---|---|
| 1 | 108.0 | 1.090 | 99.1 |
| 2 | 116.6 | 1.188 | 98.2 |
| 3 | 126.0 | 1.295 | 97.3 |
| 4 | 136.0 | 1.412 | 96.3 |
| 5 | 146.9 | 1.539 | 95.5 |
The present values of the first five years add up to roughly €486 million.
Step 2: determine the terminal value. From year 5 onwards we assume 2% perpetual growth. The formula: FCF in year 6 divided by (discount rate minus terminal growth rate), i.e. 149.8 ÷ (0.09 − 0.02) ≈ €2,140 million – that is the value of every year from year 6 onwards, as seen from year 5. Discounted back to today: 2,140 ÷ 1.539 ≈ €1,391 million.
Step 3: add everything up. 486 + 1,391 ≈ €1,877 million of company value. With 100 million shares outstanding, that works out to a fair value of roughly €18.80 per share. If the stock trades at €14, it looks cheap; at €25 it would be expensive on these assumptions.
Notice anything? Around 74% of the total value sits in the terminal value – in the distant, most uncertain part of the future. That is true of almost every DCF, and it is the main reason you should never read the result as an exact number.
Small assumption, big impact: the sensitivity trap
Two tiny tweaks to our example show how sensitive the model really is:
- A 10% discount rate instead of 9%: fair value drops from €18.80 to roughly €16.40 – a single percentage point costs about 13% of the value.
- Terminal growth of 3% instead of 2%: fair value jumps to roughly €21.30 – again a good 13%, this time upwards.
Combine both changes in the “friendly” direction each time and the gap between the pessimistic and the optimistic variant quickly reaches 40–50% – without anything about the business having changed at all. Which is exactly the point: a DCF is not a result, it is a thinking framework. It forces you to make your assumptions explicit – and shows you which of them really drive the value. Anyone who quotes you a fair value down to the last cent without disclosing their assumptions is selling false precision.
Multiples as a cross-check
Because the DCF is so sensitive to its assumptions, you should always sanity-check it with a second, simpler method: multiples. Here you compare ratios such as the P/E ratio (price-to-earnings), EV/EBIT or the free cash flow yield with the company’s own history and with its competitors. For a detailed walkthrough of the key ratios, see the guide Understanding valuation metrics.
Back to our example: with earnings of €0.80 per share, our DCF value of €18.80 would imply a P/E of roughly 23.5. If comparable companies trade at 18 times earnings on average, the multiples-based value would be closer to €14.40. That discrepancy is valuable: either the company justifies a premium through faster growth or higher quality – or your DCF is too optimistic. The two methods together are far more robust than either one on its own.
Why a range is more honest than a point estimate
The most important practical lesson from the sensitivity analysis: don’t calculate one fair value, calculate three scenarios – conservative, base and optimistic. In our example that might look like this:
- Conservative (5% growth, 10% discount rate): around €13–14
- Base (8% growth, 9% discount rate): around €18–19
- Optimistic (10% growth, 8.5% discount rate): around €23–24
The honest statement then reads: “The stock is worth roughly €13 to €24, with the weight of the evidence around €18.” That feels less satisfying than “exactly €18.80”, but it is the only intellectually honest form. For the same reason, the AI report from aktienanalyse.ai deliberately outputs a fair-value range plus scenarios rather than a single number – and if you want to see how to construct bull and bear cases properly, read the guide Bull and bear case.
Margin of safety: the buffer for your own mistakes
Even a range is still an estimate. That is why Graham added the margin of safety to the concept: only buy when the price sits clearly below your estimated value – a discount of 20–30% is standard, and more for business models that are hard to forecast.
In our example: if your base-case value is €18.80, then with a 30% margin of safety the stock only gets truly interesting below about €13. The margin is not a return booster; it is insurance against yourself – against overly optimistic growth assumptions, against surprises in the business, against plain calculation and reasoning errors. The wider your value range, the bigger the buffer should be.
Bottom line: how to do it in practice
- Understand the business model first – without that, every cash flow forecast is reading tea leaves. The guide How to analyze stocks offers a structured starting point.
- Build a simple DCF with deliberately cautious assumptions: realistic growth, a discount rate no lower than 8–9%, terminal growth of at most 2–3%.
- Cross-check the result with multiples against the company’s history and its competitors.
- Frame a range with three scenarios instead of a single point estimate.
- Buy only with a margin of safety – and write down your assumptions so you can review them later.
Once you have worked through this process by hand, you will also understand any automated valuation much better – such as the fair-value range that the AI analysis from aktienanalyse.ai derives from more than 35 fundamental metrics. The tools change, the logic stays the same: value is the discounted future – and humility about your own assumptions is always part of the deal.