Formula used
Future value = investment x (1 + r)^n, where r is the expected annual return and n is the number of years. The inflation-adjusted value divides that result by (1 + inflation)^n to show purchasing power in today's rupees.
Example calculation
Rs 1,00,000 invested once at an assumed 12% for 10 years grows to about Rs 3,10,585 — a gain of about Rs 2,10,585. Adjusted for 6% inflation, that corpus is worth about Rs 1,73,429 in today's money.
How to use this calculator
- Enter the one-time amount you plan to invest.
- Set a realistic expected annual return for the chosen asset.
- Choose the number of years you plan to stay invested.
- Set an inflation assumption to see the corpus in today's money.
Important assumptions
- A constant annual return compounded yearly; real market returns fluctuate.
- No taxes, exit loads or fund expenses are modelled.
- Educational estimate only, not investment advice or a return guarantee.
Common mistakes to avoid
- Assuming optimistic returns like 15-18% for planning.
- Ignoring inflation when judging the future corpus.
- Forgetting capital gains tax on redemption.
- Comparing a lumpsum projection against a SIP of the same monthly amount — the cashflows differ.
- Investing an emergency fund as a locked-in lumpsum.
How compounding works in a lumpsum investment
A lumpsum compounds on the full amount from day one: each year's growth is earned on both the principal and all past growth. That is why time matters more than timing — Rs 1 lakh at 12% becomes about Rs 3.1 lakh in 10 years but about Rs 9.65 lakh in 20 years, tripling the gain by doubling the period.
Lumpsum vs SIP: when each fits
Use a lumpsum when the money already exists and your horizon is long; use a SIP to invest from monthly income and to average entry prices in volatile markets.
- Lumpsum: full market exposure immediately, higher entry-point risk.
- SIP: rupee-cost averaging, suits salaried cashflows.
- Combining both is common: lumpsum for windfalls, SIP for salary.
Always check the inflation-adjusted number
A projection that looks large in nominal rupees may be modest in purchasing power. At 6% inflation, prices roughly double every 12 years, so a 10-year corpus needs to be judged in today's money — which is exactly what the inflation-adjusted output shows.
Source and Methodology
Last reviewed: July 2026
This calculator compounds your one-time investment at the assumed annual return for the chosen period and discounts the result by the assumed inflation rate. It does not model taxes, expenses or market volatility. Educational estimate only.
Educational estimate only. RupeeKit does not provide personalized financial, investment, legal, tax or loan advice.
Lumpsum is a one-time cash-flow calculation
This page isolates the future value of a single starting investment. Use the SIP calculators for recurring contributions and the XIRR page when multiple investments entered at different times need an annualised-return estimate.
Related calculators and guides
You can cross-check this estimate using: salary in-hand calculator, Old vs New Tax Regime Calculator, 80C deduction calculator, EMI calculator, ITR-2 filing guide, emergency fund guide.
When this tool is useful
- When you want a fast estimate before making a financial or salary decision.
- When you want to compare different assumptions in seconds.
- When you want to understand the formula behind the result.