Payback Period CalculatorFree online financial calculator — instant results, no sign-up
How long until cash inflows repay an investment.
Estimates only, based on the inputs and assumptions shown. This is not financial, investment, tax, or legal advice. Prices, rates and local rules may change; crypto scenarios do not predict returns. Confirm important decisions with a qualified professional.
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About the Payback Period Calculator
This calculator determines the time required to recover an initial capital outlay using constant annual cash inflows. It computes both the simple payback period and the discounted payback period, which accounts for the time value of money. Business owners, project managers, and investors use it to evaluate liquidity and project break-even horizons.
- Initial investment
- The upfront cash outflow required to fund the project or asset, measured in dollars (typically a positive value).
- Annual cash inflow
- The constant net cash generated by the investment each year, measured in dollars.
- Discount rate
- The annual cost of capital or required rate of return used to discount future cash flows, entered as a percentage.
Formula and method
Simple Payback = Initial Investment / Annual Cash Inflow Discounted Payback = -ln(1 - (Initial Investment * r) / Annual Cash Inflow) / ln(1 + r)
- rAnnual discount rate expressed as a decimal (Discount rate / 100)
- lnNatural logarithm function
The simple payback period divides the initial investment directly by the annual cash inflow. For the discounted payback period, the calculator solves the present value of an ordinary annuity equation for time using the natural logarithm. If the product of the initial investment and the discount rate meets or exceeds the annual cash inflow, the discounted cash flows will never repay the principal, and the calculator displays 'Never'.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Initial investment50000 $
- Annual cash inflow12000 $
- Discount rate8 %
Results
- Payback period4.17 years
- Discounted payback5.27 years
How to use the Payback Period Calculator
- 1Divide the initial investment by the annual cash inflow to get the undiscounted simple payback period in years.
- 2Convert the discount rate percentage into a decimal by dividing by 100.
- 3Evaluate 1 - (Initial Investment * r / Annual Cash Inflow); if this term is zero or negative, the investment never recovers on a discounted basis.
- 4Compute the natural logarithm of that term, divide by the negative natural logarithm of (1 + r), and round both results to two decimal places.
Reading your result
The simple payback period shows how many years until cumulative raw cash equals the initial cost. The discounted payback period is always longer because future cash flows are discounted to their present value. A project that shows 'Never' indicates the annual cash flow is insufficient to cover even the annual opportunity cost of capital.
Limitations
The calculator assumes cash inflows are identical and distributed evenly in annual intervals rather than fluctuating year over year. It also stops evaluating once the initial investment is recovered, ignoring any cash flows, profitability, or salvage value occurring after the payback threshold.
Common questions
Why does the discounted payback display 'Never'?+
If your annual cash flow is less than or equal to the initial investment multiplied by the discount rate, the annual return fails to cover the annual capital financing cost. Under those conditions, discounted cumulative cash inflows approach an asymptote that never reaches the initial cost.
Why is the discounted payback period always longer than the simple payback period?+
Because of the time value of money, a dollar received in the future is worth less than a dollar today. Discounting shrinks future inflows, requiring more years of cash generation to sum up to the original expenditure.
Can I use this calculator if my cash inflows vary from year to year?+
No, this specific model assumes a constant, identical annual cash inflow every year. Variable cash flows require a cumulative year-by-year subtraction method.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
Further reading
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Results are estimates for informational purposes and are not financial, medical or legal advice.