Payback Period Calculator
Find the number of years until cumulative cash flows recover an upfront investment — the classic liquidity check used in capital budgeting alongside NPV and IRR.
Simple payback (years)
3.33
- Discounted payback (years)
- 4.26
- Discount rate
- 10%
- Initial investment
- £10,000.00
- Annual cash flow
- £3,000.00
- Total cash returned (undiscounted)
- £30,000.00
- Total cash returned (discounted)
- £11,372.36
Simple payback of 3.33 years falls within the 10-year horizon. At a 10% discount rate the project recovers its cost in 4.26 years. Payback ignores cash flows after breakeven and (in the simple version) the time value of money — pair it with NPV or IRR before accepting the project.
How to use this calculator
Enter the upfront cost of the project as the initial investment and the cash flow you expect each year. Set a discount rate to compute discounted payback (use your cost of capital or required rate of return — often 8–12% for stable businesses). The project horizon caps how far the discounted payback calculation will look; pick the realistic life of the project. The calculator returns simple payback (ignoring the time value of money) and discounted payback (accounting for it) alongside the totals of cash returned over the horizon.
How the calculation works
Simple payback is C0 / CF — initial investment divided by the constant annual cash flow. Discounted payback is the smallest year T such that the sum of CF / (1 + r)^t for t = 1..T meets or exceeds C0, with the fractional year computed by linear interpolation across the year when cumulative cash flows cross zero. Discounted payback is always at least as long as simple payback because each future cash flow contributes less than its face value once discounted. Both metrics are blind to what happens after breakeven and treat the cash-flow profile as constant — they are liquidity / risk lenses, not profitability ones.
Worked example
A factory upgrade costs $10,000 today and is expected to save $3,000 a year. Simple payback = 10,000 / 3,000 = 3.33 years. With a 10% discount rate over a 10-year horizon, the discounted cash flows are 2,727.27, 2,479.34, 2,253.94, 2,049.04, 1,862.76, 1,693.42, ... Cumulative recovers the $10,000 part-way through year 5: 10,000 − (2,727.27 + 2,479.34 + 2,253.94 + 2,049.04) = $490.41 remaining, divided by year-5 cash of $1,862.76 → 0.26 of a year. Discounted payback ≈ 4.26 years.
Frequently asked questions
Is shorter payback always better?
For risk and liquidity, yes — a shorter payback means your capital is exposed for less time and you can redeploy it sooner. But payback alone can pick the wrong project. Two projects with identical payback periods can have very different lifetime profits if one ends at breakeven and the other keeps paying cash flows for another decade. Use payback as a screen ("is the upside soon enough to bear the risk?") then rank survivors with NPV and IRR.
What is the difference between simple and discounted payback?
Simple payback ignores the time value of money — a $1 cash flow in year 5 counts the same as a $1 cash flow in year 1. Discounted payback first discounts each cash flow to present value using your cost of capital, then asks the same recovery question. Because discounted cash flows are smaller, discounted payback is always at least as long as simple payback. Discounted payback is the more conservative figure and the one capital-budgeting textbooks generally prefer.
What is a reasonable payback period to require?
It depends on industry, risk, and capital cost. Manufacturing capex projects often demand payback within 3–5 years; consumer goods marketing investments might require under 2; infrastructure and real estate can tolerate 10+. The rule of thumb: payback should be well inside the asset's useful life and short enough that the cash flows you depend on are still reasonably foreseeable. If the discounted payback approaches the project horizon, the project is borderline even before considering the cash flows you would miss by tying up the money.
Why do textbooks call payback period a flawed metric?
Three reasons. First, simple payback ignores the time value of money — a real flaw that discounted payback fixes. Second, both versions ignore cash flows after breakeven, so a project with a quick payback and nothing after looks the same as one with the same payback plus a long tail of gains. Third, the accept/reject cut-off (e.g. "must pay back in 4 years") is arbitrary. NPV avoids all three issues by summing every discounted cash flow at the cost of capital. Payback is still useful as a liquidity check and as an intuitive figure to communicate, but it should not be the sole decision criterion.
How does payback relate to IRR?
Loosely. A short payback often correlates with a high IRR because most of the value comes early. But the relationship is not mechanical: a project paying $3,000 a year for 5 years and another paying $3,000 a year for 50 years have the same payback period but very different IRRs ($10k init → ≈15% vs. ≈30%). Treat payback as a liquidity/risk lens and IRR or NPV as the profitability lens.
What if my cash flows are uneven?
This calculator assumes a constant annual cash flow, which is the most common quick-look setup. For uneven cash flows, lay out the series in a spreadsheet, compute cumulative inflows (or cumulative discounted inflows) year by year, and find the year in which the cumulative first meets the initial investment. The fractional year is the shortfall going into that year divided by that year's cash flow. The decision rule is identical; only the arithmetic gets longer.