Payback, Discounted Payback and Profitability Index Calculator
Reviewed by CA Nikhil Gupta · Last reviewed 11 October 2026
Measure simple payback, discounted payback and present-value benefit per rupee invested.
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.
Finin2min decision laboratory
Two-Project Capital Budgeting Comparison
Advanced model
Compare annual cash-flow series, terminal salvage and working-capital recovery with full-horizon NPV, PI and discounted payback.
Enter assumptions and select Calculate.
Educational modelling only. Verify qualitative factors, assumptions, current tax treatment and cash-flow dates independently. Legacy calculator remains available on this page.
Payback, Discounted Payback and Profitability Index Calculator should be used as a decision-support page, not as a substitute for checking the governing rule, return data, books and supporting documents.
Use the steps below to connect the page to the governing source, the documents in hand and the next practical action. For tax, legal, labour and regulatory matters, the final position should always be checked against the official source and the facts of the specific case.
Scope: Payback and profitability index calculator for initial investment, discount rate and annual cash flows.
Reader path: Project cash flows, How This Is Calculated, Frequently Asked Questions, Evidence and verification checklist, Before relying on this page.
How to use this page
Read the page summary and identify the rule or business question the tool is designed to answer.
Enter only final, reconciled figures. Do not use provisional ledgers unless the working paper says so.
Compare the output with the legal trigger or management approval threshold.
Save the input trail, output and review note in one evidence file.
Quality checks before relying on it
Confirm every input against the latest books, portal data or statutory threshold before relying on the output.
Keep the calculator printout or screenshot with the working paper and note the assumptions used.
Re-run the calculation when turnover, dates, entity category or exemption status changes.
Use a reviewer for cases involving notices, penalties, limitation dates or audit objections.
Practical example
Example: before using Payback, Discounted Payback and Profitability Index Calculator, freeze the input period, entity type and source numbers. Run the tool once, note every assumption, and compare the result with the statutory or management threshold that triggered the check.
Documents to keep
Input worksheet or return extract
Source ledger or portal report
Calculation output
Approval note
Screenshot or PDF retained with date
Common mistakes to avoid
Using provisional numbers as final
Ignoring entity-specific exemptions
Changing an input after approval without saving a new trail
Use the source references already present on the page, and verify the controlling law, rule, form or calculation assumption before relying on the conclusion.
FAQ
Can I rely on this page without opening the official source?
No. Use this page to understand the workflow and checks, then verify the operative text, notification, order or portal instruction from the official source before filing, replying or advising.
When should I get a professional review?
Get a professional review before filing a return, issuing a notice, replying to a department communication, taking a classification position, relying on a limitation date or changing an accounting or payroll treatment.
Who reviewed this page?
Reviewed by CA Nikhil Gupta. Last reviewed 11 October 2026.
Finin2min • Indian law, tax and finance
Payback and Profitability Index Calculator: Complete capital-budgeting guide
Author: CA Nikhil Gupta | Reviewer: CA Nikhil Gupta | 11 October 2026
A payback calculator estimates when nominal project cash flows recover initial capital. Discounted payback accounts for the time value of money, while profitability index (PI) compares discounted future inflows with the initial investment. These are not interchangeable investment decisions.
Plain-language guide · Official references · Practical scenarios
Four essential decisions
Decision point
What matters
Scope and legal test
Simple payback tracks cumulative yearly undiscounted cash flows. Fractional-year recovery assumes cash flow is earned evenly within the recovery year and may overstate precision for seasonal projects.
Procedure or classification
Discounted payback uses CFt/(1+r)^t for each year t. With only positive future cash flows and a positive rate, discounted payback will generally not be shorter than simple payback.
Evidence and exceptions
The simplified PI equals PV of future net operating cash flows divided by initial cash outlay. PI above 1 implies positive NPV only under the same consistent cash-flow convention.
Outcome or follow-through
When there are negative interim cash flows, later capital injections or terminal working-capital effects, interpret a simple first-crossing payback carefully and supplement with NPV and IRR analysis.
Practical Indian example
Invest ₹1,00,000 and receive ₹60,000 in Year 1 and ₹60,000 in Year 2. Simple payback is 1 + ₹40,000/₹60,000 = 1.67 years. At 10%, PV of receipts is about ₹1,04,132; PI ≈ 1.041 and NPV ≈ ₹4,132.
Apply the facts and evidence to the particular provision before reaching a filing, tax or legal conclusion; a different date, jurisdiction or documentary trail can change the result.
What to preserve
Initial capital-cost budget and date of investment
Year-wise incremental net cash-flow forecast and terminal disposal/working-capital assumptions
Discount-rate working paper with financing assumptions and sensitivity cases
Approved project business case, alternatives and post-investment tracking report
Important boundaries and related provisions
Simple payback intentionally ignores the value of money over time, and a two-year project is not directly comparable with a ten-year project purely by payback speed. Profitability index can be helpful when budget is limited but may rank mutually exclusive projects differently from their absolute NPVs. Where cash flows change sign repeatedly, explain what a first-crossing payback number does and does not mean.
Common mistakes and how to avoid them
Using an invalid discount rate of minus 100% or less
Treating missing cash-flow fields as zero without warning
Comparing projects with different life spans on PI alone
Frequently asked questions
Can a project have positive NPV but no payback in the forecast period?
The result depends on cash-flow treatment and horizon; review complete flows and terminal values.
Does PI above 1 always mean the project should be accepted?
Not by itself. Capital constraints, risk, mutually exclusive project options and forecast reliability also matter.
Primary references
For legal wording and operative dates, consult the official source and later amendments applicable to the relevant date.
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.
Guides that use this calculator
Background, worked examples and the rules behind these numbers.