DCF: valuing a business from its future cash

The lesson in plain words

The same lesson as the slides above, written out in full.

1. Valuing a business by its future cash

Welcome. In this lesson we build the intuition behind a discounted cash flow, often shortened to DCF, one of the most common ways to estimate what a whole business is worth. The core idea is simple: a company is worth the cash it can hand you in the future, adjusted for the fact that future cash is worth less than cash in hand. Take your time here, there is no rush.

• A DCF estimates a company's worth from the cash it will produce over time.
• Future cash is pulled back, or discounted, into today's terms.
• The result is one number: an estimated value today.
• The method works for any cash-producing asset, not just stocks.
• You need only two ingredients: expected cash flows and a rate to discount them.

A quick note: This is financial education only, not financial advice. The numbers here are illustrative and chosen to make the idea clear, not real forecasts for any company.

2. A dollar later is worth less than a dollar today

Here is the heart of it. If I offered you a dollar right now or the same dollar in five years, you would take it now, and you would be right to. Money in hand can earn a return in the meantime, and a promise about the future carries some chance it never pays out. That is why a DCF marks future cash down before counting it.

• This gap is called the time value of money.
• Cash today can be put to work and grow before that future date arrives.
• Waiting also adds uncertainty: the future cash may be smaller or may not arrive.
• So a future dollar is always worth less than a dollar in hand.
• The bigger the wait or the risk, the steeper the shrink.

3. Discount each year, then add them up

Now we put the pieces together. Imagine a business throwing off a hundred dollars a year. We do not add five raw hundreds. Instead we shrink each year according to how far away it is, so the first year might count as ninety-three and the fifth as sixty-eight. Add those discounted pieces up and you have one clean number: the value today.

• You forecast the cash flows a business is likely to produce each year.
• Each year is shrunk using a discount rate that reflects wait and risk.
• Cash further out is discounted more, so later years count for less.
• Add every discounted year together to get the present value.
• That single sum is the DCF's estimate of what the business is worth now.

4. The answer is only as good as the assumptions

Here is the honest part. A DCF is only as trustworthy as the assumptions you feed it. Nudge the growth rate or the discount rate a little and the answer can move dramatically, which is why two careful people can build very different valuations of the same company. So use it to understand the drivers of value and to stress test your thinking, not to produce a single number you treat as truth.

• A DCF rests on estimates of the future, not on facts.
• Small changes to the growth rate can swing the final number a lot.
• The discount rate you pick reshapes how heavily later years count.
• A large share of the value often sits in the terminal value, the assumed end value.
• Treat the output as a range and a reasoning tool, never a guaranteed price.