How it's calculated
A lump-sum investment puts the whole amount to work on day one. At a constant yearly return it compounds: every year the return is earned on the original amount plus all the returns before it. The calculator shows the value at the end of each year and the total gain.
AMFI's lumpsum calculator uses the same compound-interest formula with yearly compounding: ₹2 lakh at 12% for 10 years grows to ₹6,21,169.64.AMFI The calculator gives ₹6,21,170 (rounded to the rupee).
The formula
Future value = P × (1 + r)t, where P is the amount invested, r the expected yearly return and t the number of years. Gains = future value − P.
A quick check is the rule of 72: money doubles in about 72 ÷ (return in %) years, so roughly 6 years at 12% and 7 years at 10%.
Worked example
₹1 lakh invested for 10 years at an assumed 12% a year grows to ₹3,10,585, a gain of ₹2,10,585.
| Line | Amount |
|---|---|
| Amount invested | ₹1,00,000 |
| Estimated gains at 12% a year | ₹2,10,585 |
| Estimated value | ₹3,10,585 |
Left for 20 years, the same ₹1 lakh grows to ₹9,64,629: the second decade adds far more than the first because the gains themselves compound.
Assumptions and limitations
- A constant return. Equity funds can fall sharply in some years; the result is an estimate at the return you enter, not a forecast.
- Before capital gains tax and exit loads. Expense ratios are already reflected in a fund's NAV.
- No further investments or withdrawals. To add a monthly amount, use the SIP calculator.
- For deposits with a published rate, such as the PPF, use the PPF calculator, which follows that scheme's own interest rules.AMFI