How the Lumpsum Calculator works
A lump sum investment is a single, one-time amount put to work all at once — as opposed to a Systematic Investment Plan (SIP) where you contribute smaller amounts on a recurring schedule. This calculator projects how that single deposit grows over time using standard compound interest, so you can see the maturity value, the total gain, and the return percentage for a given rate, term, and compounding frequency.
The formula
For a principal P, an annual rate of return r (as a decimal), a compounding frequency n (times per year), and a term of t years, the maturity value is:
FV = P × (1 + r/n)n×t
The wealth gained is simply FV − P, and the absolute return is (FV − P) / P expressed as a percentage. Annual compounding uses n = 1; semi-annual uses n = 2; quarterly uses n = 4; monthly uses n = 12; and daily uses n = 365.
Worked example
Invest $100,000 for 10 years at an expected 10% annual return, compounded monthly. With n = 12 and t = 10, the periodic rate is 0.10 / 12 and there are 120 compounding periods. The formula gives a maturity value of roughly $270,704 — a gain of about $170,704, or a 170.70% total return over the decade.
What moves the maturity value most
- Rate of return: because growth compounds, small differences in the assumed annual rate produce large differences in the final value over long periods.
- Time invested: the effect of compounding accelerates the longer money stays invested — doubling the term more than doubles the total growth at a positive rate.
- Compounding frequency: more frequent compounding (monthly or daily versus annually) increases the effective yield slightly, since interest starts earning interest sooner.
Lump sum versus SIP
A lump sum puts the full amount to work immediately, so it benefits fully from compounding from day one — but it also carries full market-timing exposure if the return varies year to year, since this calculator assumes one constant rate. An SIP spreads the investment across many smaller purchases over time, which averages the entry price but delays when later contributions start compounding. This calculator only models the lump sum case; a real investment's actual annual returns typically vary rather than staying constant.
Getting accurate results
- Enter the rate as an annual percentage (e.g., 10 for 10%), not a decimal.
- The result assumes a constant annual rate of return for the entire period — real markets fluctuate year to year, so treat the output as an illustrative projection, not a guarantee.
- This calculator does not account for taxes, fees, or inflation; subtract those separately if you want a real (inflation-adjusted) or after-tax figure.