TL;DR: A reverse DCF runs a valuation model backwards. Instead of guessing a growth rate to get a value, you take the market price as given and solve for the growth rate the price already assumes. The output is not what a stock is worth. It is what has to be true for today's price to make sense, in one number you can actually argue with.
What is a reverse DCF?
A discounted cash flow model projects a company's free cash flow forward, then discounts that stream back to today at a required return. Feed in a growth rate, get a value. That is the forward direction, and it has a well-known weakness: the answer is mostly the growth guess wearing a suit. Small changes to the assumption swing the value wildly, so the model often just returns your own optimism with decimal places.
The reverse DCF flips the trade. The price is observable; the growth rate is not. So hold the price fixed, run the same model, and search for the growth rate that makes the model's value exactly equal the market price. That rate is the expectation embedded in the price, set by everyone who has bought and sold the stock. You did not invent it. The market did, and now you can read it.
Our reverse DCF calculator runs this live on your own inputs. This post is the method behind it: what the number means, how to sanity-check it, and the four places it misleads.
How do you run one? A worked example
You need four inputs: the current share price, free cash flow per share (trailing twelve months is the usual base), a discount rate, and a terminal growth rate for the years after the projection window. Take a concrete case:
- Price: $100.00
- Free cash flow per share: $5.00
- Discount rate: 10 percent
- Terminal growth: 3 percent, over a ten-year window
The model solves to 7.15 percent annual growth in free cash flow per share, sustained for ten years. That is what the $100 price assumes. One calibration point helps the number land: hold growth at zero across the whole ten-year window, keeping the same 3 percent terminal rate after it, and the same cash flow stream is worth $59.09 in this model. (Zero growth literally forever, no terminal uplift at all, would be worth $50.00, the cash flow divided by the discount rate.) So roughly forty dollars of the price is not payment for the business growing slowly. It is payment for growth that has not happened yet.
Now move only the price. At $50.00, on $4.00 of free cash flow per share, implied growth falls to 0.77 percent a year. The market is pricing in near stagnation; merely ordinary performance clears the bar. At $200.00, on the same $5.00 of cash flow as the first example, implied growth jumps to 16.49 percent a year for a decade. Very few large companies in market history have compounded cash flow at that pace for that long. The price is not necessarily wrong. It is necessarily demanding, and now the demand is a number instead of a feeling.
How much do the assumptions move the answer?
A lot, and honesty requires showing it. Rerun the first example with a 9 percent discount rate instead of 10, and implied growth falls to 5.00 percent. At an 11 percent discount rate it rises to 9.14 percent. Drop the terminal growth rate from 3 percent to 2, and implied growth rises to 8.23 percent, because less of the value can come from the distant future, so more must come from the next ten years.
This is why a quoted implied growth figure means nothing without its discount rate attached. Two careful analysts can look at the same stock and report numbers four points apart, both correctly, because they require different returns. The reverse DCF does not settle that argument. It forces it into the open, which is where investment arguments belong.
How do you judge whether the implied growth is believable?
Three comparisons do most of the work:
- Against the company's own history. Has it ever grown cash flow at the implied rate for a decade? A rate the company has already achieved is a different claim from one three times faster than anything in its record.
- Against the size of the prize. A small company can double for years before it strains its market. Work out what the implied rate makes any company by year ten, in plain revenue or cash flow terms, and ask where that money comes from. For a company that already dominates its industry, that question gets hard to answer quickly, and the difficulty is the information.
- Against your own forecast. If your honest, research-backed growth estimate sits comfortably above the implied rate, the price is asking less than you expect: that is the shape of an opportunity. If your estimate sits below it, the price needs a better story than the one you believe, and the burden of proof is on the story.
Notice what none of this produces: a buy or sell instruction. A high implied rate is a burden-of-proof signal, not a verdict. Companies sometimes deliver heroic growth. The reverse DCF's job is to make you state, before you commit capital, exactly how heroic the delivery has to be.
Where does a reverse DCF mislead?
- Lumpy cash flow. A single year of heavy investment can crush free cash flow and inflate the implied rate into nonsense. For cyclical or fast-building companies, feed the model a normalized or multi-year average figure instead of one unusual year.
- Buybacks hide inside per-share numbers. Free cash flow per share rises when the share count falls, even if the business itself is flat. Part of any implied rate is buyback pace, not business growth. Decide which of the two you actually believe in before you trust the blend.
- The constant-rate fiction. The model solves for one smooth growth rate. Real growth arrives unevenly, fast early and slower later, or the reverse. Read the answer as the average pace the price requires, never as a year-by-year prediction.
- It prices cash, not quality. Moats, management, and competitive position never appear as inputs. Two stocks can carry identical implied growth rates and wildly different odds of delivering them. The reverse DCF tells you what has to be true. Your research decides whether it is.
How does it fit next to the other valuation tools?
These valuation approaches answer different questions. The Graham Number asks a backward-looking question: at this price, am I overpaying against today's earnings and assets? Graham's own growth shorthand, the Benjamin Graham formula, asks a related question with earnings and expected growth in one line. The forward DCF asks: given what I believe, what is this worth? The reverse DCF asks the question that disciplines the others: given this price, what must I believe?
Run the reverse calculation first and the forward one gets harder to fudge, because you build your model knowing exactly which assumption the market has already made. Inside FullPort, both directions sit on live company financials next to the full toolkit: start free and run them on your own watchlist. And when a name survives the valuation work, the cheapest next step costs nothing: paper trade the strategy first and watch live prices grade the thesis before real capital does.
Educational content, not financial advice. A reverse DCF describes the expectations embedded in a price under stated assumptions. It is not a valuation of any specific company and not a recommendation to buy or sell any security.
