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ToolBoxGenie

Lumpsum Calculator

Calculators · Added 14 August 2026

A single amount invested once and left alone is the simplest case in all of investing, and the clearest demonstration of compounding. Enter the amount, the return you expect and the period, and this calculator shows the projected value with the year-by-year path underneath.

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Your assumption, not an offer.

yrs

How to use the lumpsum calculator

  1. 1Enter the amount you are investing in one go.
  2. 2Enter the annual return you want to assume. This is your assumption about the future, not a rate anyone is offering.
  3. 3Set the number of years.
  4. 4Press Calculate to see the projected maturity value and the profit on top of what you put in.
  5. 5Open the year-by-year table to see where the growth actually accumulates — the last few years carry far more of it than the first.

Examples

A decade at 12%

Input
₹1,00,000 at 12% for 10 years
Result
₹3,10,585 — a profit of ₹2,10,585, or 3.11× the amount invested

The rule of 72 gives a rough check: 72 ÷ 12 is six years to double, so ten years is a little over one and a half doublings.

The same money for twenty years

Input
₹1,00,000 at 12% for 20 years
Result
₹9,64,629 — 9.65× the amount invested

Doubling the period more than triples the result. The second decade produces far more than the first.

What two percentage points cost

Input
₹10,00,000 for 20 years at 10% against 12%
Result
₹67,27,500 against ₹96,46,293 — a difference of about ₹29,18,793

Over long periods, small differences in return — including fees — become enormous differences in outcome.

About the lumpsum calculator

Compounding, and why the last years dominate

The formula is the shortest in finance: future value equals principal times (1 + rate) to the power of years. Everything interesting about it follows from that exponent. Growth is applied to a base that itself keeps growing, so each year adds more in absolute terms than the one before, even at a constant rate.

The practical consequence shows up clearly in the year-by-year table. On ₹1,00,000 at 12%, the first year adds ₹12,000 and the tenth adds about ₹33,000 — nearly three times as much, from the same percentage. Extend to twenty years and the twentieth year alone adds more than the first six combined.

This is why the period matters more than almost anything else, and why the rule of 72 is worth carrying around: divide 72 by the return to get the approximate doubling time. At 12% that is six years, so a twenty-year horizon is a bit over three doublings — the difference between roughly three times your money and roughly ten.

Why small differences in return are not small

Two percentage points sounds like a detail. Over twenty years on ₹10,00,000 it is worth about ₹29 lakh — nearly three times the original investment. That gap is the whole argument for taking costs seriously, because an expense ratio is a direct subtraction from your return, applied every year, compounding against you exactly as returns compound for you.

It cuts the other way too, and this is where honesty is required. If two percentage points of return matter that much, then the difference between a 12% assumption and a 10% one is not a modelling nicety — it is a completely different plan. Anyone presenting a single confident long-run projection is understating the uncertainty, including this page when read carelessly.

The defensible use of a calculator like this is comparative rather than predictive. Run it at several rates. Notice how much the answer moves. Build the plan around the pessimistic end and treat the optimistic end as upside, rather than the other way round.

Frequently asked questions

Lumpsum or SIP?
They answer different situations rather than competing. If you already hold the money, a lump sum puts all of it to work immediately, which mathematically wins in a rising market — most markets, most of the time. A SIP is what you do with income as it arrives. The genuine argument for staggering a lump sum is behavioural: it limits the regret of investing everything the day before a fall, at a modest expected cost.
Is the maturity value guaranteed?
No. The figure is a projection conditional on a constant annual return, and no market-linked investment delivers a constant return. The calculator answers 'if the average were exactly this, the result would be that' — the real path will be jagged and may sit below the projection for years at a stretch.
Does the order of good and bad years matter?
For a lump sum left completely alone, no — multiplication commutes, so the same set of annual returns in any order produces the same final value. This stops being true the moment you add or withdraw money, which is why SIP and SWP projections carry warnings about sequence risk that this one does not.
Are fees and tax included?
No. Enter a return net of the expense ratio if you want costs reflected — subtracting the expense ratio from your assumed return is the usual approximation. Exit loads and capital gains tax on redemption are not modelled at all, and both reduce what actually reaches you.

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