Discounted Payback Period Calculator
Calculate the discounted payback period — how long it takes to recover an investment when future cash flows are discounted to their present value. This is a more rigorous version of simple payback because it accounts for the time value of money.
Year-by-Year Breakdown
| Year | Cash Flow | Discount Factor | PV | Cumulative PV | Remaining |
|---|
What Is Discounted Payback?
Discounted payback is a refined version of the payback period that accounts for the time value of money. Instead of counting every future dollar as equal, it discounts each cash flow back to today's value at a required rate of return, then measures how long it takes the discounted (present-value) cash flows to equal the initial investment.
The result is always longer than simple payback — because future cash flows are worth less in today's money. Discounted payback is a stricter test: if a project barely passes simple payback but fails discounted payback, it may not be worth pursuing.
Discounted Payback Formula
Step 1 — Discount each year's cash flow:
PV = Cash Flow ÷ (1 + r)ⁿ
Step 2 — Sum PVs year by year until cumulative PV ≥ initial investment:
Discounted Payback = Years Before Recovery + (Unrecovered PV ÷ PV in Recovery Year)
- r — discount rate (usually WACC or required return)
- n — year number
- Discount factor = 1 ÷ (1 + r)ⁿ
Worked Example
Investment of $100,000, discount rate 10%, cash flows $25K, $30K, $35K, $40K, $45K:
Year 1 PV = $25,000 ÷ 1.10 = $22,727 (cumulative: $22,727)
Year 2 PV = $30,000 ÷ 1.10² = $24,793 (cumulative: $47,520)
Year 3 PV = $35,000 ÷ 1.10³ = $26,296 (cumulative: $73,816)
Year 4 PV = $40,000 ÷ 1.10⁴ = $27,321 (cumulative: $101,137)
Recovery happens in Year 4. Unrecovered at end of Year 3 = $100,000 − $73,816 = $26,184.
Discounted payback = 3 + ($26,184 ÷ $27,321) = 3.96 years
Discounted Payback vs Simple Payback
- Simple payback — ignores time value of money. Easier to compute but treats distant cash flows as equally valuable as near-term ones.
- Discounted payback — accounts for time value. More accurate but requires a discount rate input, and the result is sensitive to that rate.
- Gap between them — the larger the gap, the more the project depends on cash flows that are far in the future. A large gap is a warning sign for high-risk or long-term projects.
- Still limited — discounted payback still ignores cash flows after the payback period. NPV and IRR remain the more complete metrics.
Frequently Asked Questions
What is a good discounted payback period?
It depends on industry and risk. For most businesses, 3–5 years is acceptable. Anything over 5–7 years is a warning sign — long payback means more exposure to interest rate changes, market shifts, and unforeseen events. Compare against simple payback: if discounted payback is much longer, the project is highly dependent on distant cash flows.
What discount rate should I use?
Use your WACC (weighted average cost of capital) or the minimum return you require for that risk level. For a small business, 10–15% is typical. For a large, low-risk company, 6–10% may be appropriate. Higher discount rates make distant cash flows worth less, which lengthens the discounted payback period.
Why is discounted payback always longer than simple payback?
Because discounting reduces the value of every future cash flow. Simple payback counts a $1,000 Year 5 cash flow as $1,000; discounted payback counts it as $621 (at 10%). Since each year's contribution is smaller, it takes longer to accumulate enough PV to recover the initial investment. The higher the discount rate, the bigger the gap.
Does discounted payback always lead to the right decision?
Not always. It is better than simple payback because it accounts for time value, but it still ignores cash flows after the payback period. A project that recovers investment in 4 years and then generates huge cash flows for 10 more years could have the same discounted payback as a project that recovers in 4 years and then generates nothing. Use NPV or IRR for final decisions.
What if the project never recovers investment on a discounted basis?
If the cumulative discounted cash inflows never equal the initial investment, the discounted payback period is "never" or "infinite." This means the project does not earn back its cost even in present-value terms. That is a strong signal to reject the project — it destroys value.
When should I use discounted payback over NPV?
Never as the primary decision metric. NPV is always the more reliable measure. But discounted payback is useful as a secondary check: it tells you how quickly you get your money back in today's dollars, which matters for cash-constrained businesses. Use discounted payback as a risk screen, and NPV as the final decision criterion.