Discounted Payback Period Calculator
When the money comes back, once the wait is priced in.
Work out Discounted Payback Period. When the money comes back, once the wait is priced in. Shows the working period by period rather than one number.
Negative for money going out. Not discounted.
Discounted payback period
3.02 years
against 2.50 years undiscounted
Discounting adds 0.52 years to the recovery, because cash arriving in year four is not worth its face value today. Both figures share the same blind spot: everything after the payback date counts for nothing, so a project that recovers quickly and stops will beat one that recovers slowly and runs for decades.
How the Discounted Payback Period Calculator works
Payback asks how long until the investment is recovered. The discounted version asks the same thing after each year's cash has been brought back to today, which always takes longer and sometimes never happens at all. That second case is the useful one: a project can pay back on paper and never recover in present value terms, and only the discounted calculation says so.
Also known as: discounted payback calculator · payback period with discount rate · discounted payback period formula calculator
The calculation itself
Discount each cash flow, accumulate them, and find where the running total crosses zero. That crossing point is the discounted payback period.
Simple payback does the same on undiscounted cash. It is always the shorter of the two at any positive rate, because it credits later money at face value.
The fractional part is linear interpolation within the crossing period, which assumes cash arrives evenly through the year. That is the standard convention and mildly optimistic; assuming it all arrives at the period end rounds up to a whole year.
In practice
A $1,000 investment returning $400 a year for five years, discounted at 10%.
Undiscounted, the cumulative reaches −$200 after two years and the third year's $400 covers it halfway through: 2.5 years.
Discounted, the cumulative runs −$1,000, −$636, −$306, −$5, then +$268. It is still $5 short at the end of year three and crosses just into year four: 3.02 years.
Discounting adds about six months, and that near-miss at year three is the point. On undiscounted cash the project looked recovered with room to spare; in present value terms it had not quite got there.
When it never pays back
If the discounted cumulative never turns positive, the present value of everything the project produces is less than it cost. That is a negative NPV stated from the other direction.
It is a genuine result rather than a calculation failure, and this page says so instead of returning a large number. A project can pay back comfortably on undiscounted cash and never recover in present value terms — which is precisely the illusion discounting exists to remove.
The gap between those two answers is widest for long, slow projects at high rates, which is also where the intuitive appeal of simple payback is strongest.
Where the figure deceives
Payback ignores everything after the payback date, and this version inherits that completely. A project recovering in three years and stopping beats one recovering in four and running profitably for twenty, on this measure and on no sensible one.
So it is a risk screen rather than a value measure: it answers how long the money is exposed, not how much the project is worth. Used as the deciding rule it systematically favours short, small projects.
It is also silent on scale. Two projects with identical payback periods can differ by an order of magnitude in what they eventually return.
Acting on it
Use it alongside NPV, never instead. Payback tells you about exposure; NPV tells you about value.
Where capital is genuinely constrained or the environment is uncertain, a payback ceiling is a defensible screen — just apply it to the discounted figure, since the undiscounted one flatters every long project.
If a project fails discounted payback but passes NPV, the question is whether you can tolerate the exposure, not whether the project is good.
Not financial advice. This calculator is for planning and illustration, not financial advice. Real products carry fees, taxes, and terms it does not model. Confirm figures with your lender or a qualified adviser before committing.
Frequently asked questions
What is discounted payback period?
The time until cumulative discounted cash flow turns positive. It is longer than simple payback at any positive rate, because the later cash counts for less than its face value.
Why is discounted payback better than simple payback?
Because simple payback treats a dollar in year five as equal to a dollar today, which is the error the whole discipline exists to correct. It is still a crude measure, but it is crude about the right quantity.
What does it mean if it never pays back?
The present value of everything the project produces is less than what it cost — the same statement as a negative NPV, arrived at from the other direction. It is a genuine result, not a calculation failure.
Why is payback a poor decision rule?
It ignores everything after the payback date. A project recovering in three years and stopping beats one recovering in four and running for twenty, on this measure and on no sensible one.
Should the fraction of a year be interpolated?
It is here, which assumes cash arrives evenly through the period. That is the standard convention and slightly optimistic; assuming it arrives at the period end rounds the answer up to a whole number.
Put this calculator on your own site
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