Discounted Cash Flow Calculator

What a discounted cash flow model does

Money that arrives later is worth less than money you hold today, and a discounted cash flow model puts a number on the gap. Each future payment is shrunk by a discount rate to reflect the wait, then the shrunken amounts are added into one present value for the whole investment. A dollar received next year is worth less than a dollar in your hand because today's dollar can be invested and grow.

The math is a chain of discounts. Take the cash a business or project produces in year one, divide it by one plus the discount rate, and you have its present value. Do the same for year two, but discount twice, because that money is two years away. Keep going for every year, add a terminal value for everything beyond the forecast, and the total is the DCF value. Subtract what you pay today and the remainder is the net present value, or NPV.

This is the method public companies and buyers use to price a business, and the company filings on SEC EDGAR show it sitting behind most valuation footnotes. The tool above runs the same chain for any outlay, cash flow, discount rate and terminal value you enter.

The discount rate is the whole story

Every other input in a DCF is a forecast you defend with evidence. The discount rate is the lens you view those forecasts through, and small changes in it move the answer more than most people expect. Raise the rate from 8 percent to 12 percent and a ten year stream of $50,000 a year falls from about $335,504 to about $282,511 in present value, a drop of roughly $53,000 from a four point move.

For a publicly traded firm the rate often starts from the weighted average cost of capital, which blends the cost of debt and the return shareholders demand. For a small business or a project, buyers use a higher rate to cover risk and illiquidity, commonly 12 percent to 20 percent. Investor.gov explains the discount rate in plain terms, and the higher it is, the less future cash is worth today.

One refinement changes the timing slightly. The formula above assumes every cash flow lands at the end of its year, which is the conservative choice. Many analysts use a mid-year convention instead, discounting year one by half a year, because cash trickles in through the twelve months rather than arriving on the last day. On the $50,000 stream at 10 percent, that shift raises the value by about 5 percent, close to $15,000 over ten years. A stub period handles a partial first year when the forecast starts mid-calendar, and both adjustments matter most when the discount rate is high.

Worked example: a small business throwing off $50,000 a year

Suppose you can buy a vending route, laundromat, or service business that pays out $50,000 of owner earnings every year, and you expect that to hold for ten years, after which you sell it for $200,000. You want a 10 percent return. The present value of the ten yearly payments at 10 percent is about $307,228, and the present value of the $200,000 sale ten years out is about $77,109, so the DCF value is roughly $384,337.

If the seller asks $300,000, the NPV is about $84,337, meaning the price leaves that much value on the table at your required return. If the seller asks $420,000, the NPV turns negative at about minus $35,663, and the deal destroys value unless your cash flow or growth assumptions improve. The calculator shows both the DCF value and the NPV against your entered outlay.

The same business at an 8 percent rate is worth about $428,143, because cheaper money makes future cash more valuable. That swing of more than $40,000 from a two point rate change is why two reasonable buyers can quote sharply different prices for the identical cash flow.

Worked example: a project that loses money early

DCF handles negative years without complaint, which is where it beats a simple payback guess. A solar or equipment project might cost $100,000 up front, lose $10,000 in year one as it ramps, then throw off $25,000, $30,000 and $35,000 in the next three years before a $60,000 salvage value. Discount those at 10 percent and the present values are about minus $9,091, $20,661, $22,539 and $23,905, plus about $40,981 for the salvage, for a DCF value near $98,996.

Against the $100,000 outlay the NPV is about minus $1,004, so at a 10 percent hurdle the project roughly breaks even and a slightly higher rate would sink it. Raise the discount rate to 14 percent and the value falls to about $86,962, turning a near pass into a clear rejection. The early loss matters less than the rate, because the loss is discounted only once while the later gains are discounted three and four times.

This is the discipline a DCF enforces: it refuses to treat a dollar next year the same as a dollar today, so a long payoff has to clear a higher bar than a fast one. The Bureau of Labor Statistics inflation data is one place buyers look to sanity check the rate they choose against the cost of waiting.

Terminal value and why it dominates

No one forecasts cash flows forever, so a DCF ends the explicit years with a terminal value: a single number standing in for everything the business earns after the forecast ends. The trouble is that this one line often carries more weight than all the forecast years combined, because it is discounted from the far end of the timeline.

In the $50,000 a year example, the ten explicit years are worth about $307,000 at a 10 percent rate, but the $200,000 terminal value adds another $77,000, or about 20 percent of the total. Stretch the terminal value to $300,000 and the DCF jumps to roughly $422,891, a $38,554 move from one assumption about the exit. A small error in the terminal value dwarfs a small error in year three's cash flow.

The common way to set it is a perpetuity: take a steady final year cash flow, divide by the discount rate minus a long run growth rate, and discount that back. At 10 percent with 2 percent growth, $50,000 a year becomes a terminal value near $625,000, which would push the whole DCF to about $548,193. That sensitivity is the reason analysts show the terminal value as its own line and stress test it.

When a DCF lies to you

A DCF is only as honest as its inputs, and the inputs are forecasts. The biggest lie is a growth rate that runs forever at a rate above the economy, which produces a terminal value so large the operating years barely matter. Keep the long run growth at or below the inflation or GDP rate, around 2 percent to 3 percent, and the model stays believable.

The second lie is a discount rate chosen to make the answer fit a price you already like. If you need 6 percent to clear a $400,000 ask but the business is risky enough to deserve 14 percent, the honest model says no. Pick the rate from the risk, not from the deal. The third is ignoring that cash flows are estimates with ranges, so report a DCF as a band, say $350,000 to $450,000, rather than a single false precision.

None of this makes the method useless. It makes it a disciplined way to translate a story about the future into a number you can compare with a price. The number is wrong the moment the story changes, which is exactly why you recompute it before every decision rather than once and for all.

DCF versus the other ways to size up an investment

DCF is the intrinsic method: it builds value from the cash the asset produces. Multiples are the relative method: they price the asset as a multiple of revenue or earnings that similar assets sold for, which is faster but leans on the market being right. A small business priced at three times owner earnings might look cheap until a DCF shows the earnings are fading.

Payback period answers a narrower question, how long until the outlay returns, and ignores everything after that point and the time value of money. IRR flips the DCF around: instead of setting a discount rate to get a value, it finds the rate that makes the NPV zero. They are cousins, and a deal with a strong DCF value almost always shows a healthy IRR.

Use DCF when the cash flows are the point, as with a business, a rental, or a project with a clear lifespan. Use a multiple when you need speed and comparable sales. The calculator above gives you the intrinsic view, and the related tools cover the rest of the picture.