Payback, Discounted Payback and Profitability Index Calculator
Reviewed by Finin2min Editorial Desk · Last Reviewed 12 September 2026
Measure simple payback, discounted payback and present-value benefit per rupee invested.
2-minute answer
Calculate simple payback, discounted payback and profitability index from investment, discount rate and annual cash flows, with interpretation and scenario checks.
Current-law check: Reviewed for source/currentness on 12 September 2026. Re-check any later notification, circular, amendment, rate, deadline or portal instruction before acting.
How to use this page
Payback, Discounted Payback and Profitability Index Calculator is best used as a structured decision tool. Enter or compare like-for-like inputs, make the assumptions explicit and test a downside case before relying on the output.
Practical checklist
Use inputs from dated statements, contracts or operating records instead of rough estimates where possible.
Keep units and periods consistent (monthly vs annual, pre-tax vs post-tax, nominal vs real).
Run at least one conservative scenario and identify the assumption that drives the result most.
Use the result as screening evidence and document any professional or legal adjustment separately.
Worked use case
Example: if one assumption changes the answer materially, show that variable as a range instead of presenting a single-point result as certain.
Reviewed for currentness: 12 September 2026. Educational/professional reference; the controlling law, notification, order or official filing instruction prevails.
Project cash flows
Simple payback
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Discounted payback
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Profitability index
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NPV
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Calculation guidance will appear here.
How This Is Calculated
Simple payback period is how long until cumulative (undiscounted) cash flows recover the initial investment. Discounted payback does the same using discounted cash flows, taking longer to reach recovery than simple payback since it accounts for the time value of money. Profitability index (present value of future cash flows ÷ initial investment) helps rank projects of different sizes.
Frequently Asked Questions
Why is discounted payback always longer than simple payback?
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Because discounting reduces the value of future cash flows, it takes more nominal cash flow to reach the same discounted recovery amount — so discounted payback period is always equal to or longer than simple payback for the same cash flow series.
What does the profitability index add beyond NPV?
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Profitability index expresses value created per rupee invested (as a ratio), which is useful for ranking and comparing projects of different sizes when capital is limited — a project with lower absolute NPV but a higher profitability index can be more efficient use of scarce capital.
Confirm the current, in-force text governing Payback, Discounted Payback and Profitability Index Calculator on the official source linked above - the summary on this page is an implementation aid, not a substitute for it.
Record the exact event/transaction date, since the applicable version of the law, form or threshold can change between the date of the underlying event and today.
Preserve the primary documents (notices, applications, orders, acknowledgements) that would let a reviewer reconstruct how the facts were classified and what was actually done.
Check for a State-specific rule, later amendment or binding judicial decision that may modify how this applies on your facts.
Before relying on this page
This page is a structured implementation summary, not the operative legal text. Portal or process acceptance of a filing does not by itself establish legal compliance - the underlying classification, authority, evidence and timeline still have to be independently correct. Where the facts are contested, high-value, or time-barred if delayed, verify the current position with the official source and, where appropriate, a qualified professional before acting.
Scope: Computes the payback period, discounted payback period, and profitability index for an investment, to complement NPV/IRR analysis with liquidity and capital-efficiency measures.
Calculation logic
Payback period = the time (in years, interpolated to fractions of a year) at which cumulative undiscounted cash inflows equal the initial investment.
Discounted payback period = the same calculation but using cash flows discounted at the entered rate before cumulating them, giving a more conservative (typically longer) payback estimate.
Profitability Index (PI) = (Present value of future cash inflows) ÷ Initial investment; a PI above 1.0 indicates the investment is expected to create value at the given discount rate, consistent with a positive NPV.
Inputs and assumptions
Payback period is a liquidity/risk measure and does not account for the time value of money on its own — the discounted payback period addresses this by using the same discount rate as NPV.
Cash flows are assumed to occur at period-end unless specific dates are entered.
Exclusions and edge cases
Payback period ignores cash flows occurring after the payback point entirely — it should be read alongside NPV/IRR, not as a standalone investment decision rule, which the calculator's output notes explicitly.
Does not compute a hurdle payback threshold automatically — the user compares the result against their own organisation's policy.
Sources
No external regulatory source applies — this is a general financial formula, not a statutory computation.
Review status: reviewed and approved by CA Nikhil Gupta on 18 July 2026.