Payback Period Calculator
How long until your investment pays for itself? Calculate simple payback, discounted payback, and compare projects side by side.
Try another scenario
Calculate for your country ▼
How to Use This Calculator
Tab "Simple Payback"
Enter the initial investment (upfront cost) and the annual cash flow you expect to receive each year. The calculator divides the investment by the annual cash flow to give you the payback period in years. This method assumes equal cash flows every year and does not account for the time value of money.
Tab "Discounted Payback"
Enter the same investment and cash flow, plus a discount rate (your required return or cost of capital). The calculator discounts each year's cash flow to its present value, then finds the year where cumulative discounted cash flows equal or exceed the investment. The result is always longer than the simple payback because future money is worth less today.
Tab "Compare Projects"
Enter the investment and annual cash flow for two projects. The calculator shows which project pays back faster using the simple payback method. Use this to rank competing capital expenditures by risk — the shorter the payback, the sooner you recover your capital.
The Formulas
Payback Period = Initial Investment / Annual Cash Flow
Discounted Cash Flow for year n:
DCF(n) = Annual Cash Flow / (1 + r)^n
where r = discount rate as a decimal
Discounted Payback Period:
Find the smallest year Y where:
Sum of DCF(1) + DCF(2) + ... + DCF(Y) ≥ Initial Investment
Interpolation for fractional year:
Exact payback = (Y − 1) + (Remaining amount / DCF at year Y)
All calculations use standard capital budgeting mathematics. No country-specific tax rates or incentives are applied. Results are pre-tax estimates.
Worked Examples
Example 1 — Solar Panels: $15,000 investment, $2,500/year
A homeowner installs solar panels for $15,000 and saves $2,500 per year on electricity bills.
Calculation: $15,000 / $2,500 = 6.0 years. After 6 years, the solar panels have paid for themselves entirely through energy savings.
Example 2 — Same solar panels, discounted at 5%
The same $15,000 investment with $2,500/year cash flows, but now we account for a 5% discount rate (cost of capital).
With a 5% discount rate, the payback period stretches from 6.0 to approximately 7.1 years. The extra 1.1 years reflects the cost of tying up capital — future dollars are worth less than today's dollars.
Example 3 — Compare: Project A ($50K, $15K/yr) vs Project B ($80K, $22K/yr)
A business is choosing between two equipment upgrades with different costs and expected returns.
| Project | Investment | Annual CF | Payback |
|---|---|---|---|
| Project A ★ | $50,000 | $15,000 | 3.3 years |
| Project B | $80,000 | $22,000 | 3.6 years |
Project A pays back in 3.3 years vs 3.6 years for Project B. Although Project B generates more absolute cash flow ($22K vs $15K), Project A recovers its smaller investment faster. If minimizing risk is the priority, Project A wins. For total profitability, also consider ROI and NPV.
Frequently Asked Questions
Calculate for Your Country
For country-specific investment and business calculators that account for local tax rules and incentives: