Rule of 72
A quick way to estimate doubling time: divide 72 by the annual return. At 12% your money doubles in about 6 years; at 8%, about 9 years. Over 24 years at 12% that's four doublings, or 16× the original amount.
Related: SIP calculator · CAGR calculator · SWP calculator
How to use the Lumpsum Calculator tool
- Enter the amount you will invest once.
- Set the expected annual return and the number of years.
- See the future value and the year-by-year growth.
Why SaralKit?
- Free forever: no "credits", no trial, no premium tier, no watermark and no daily limit.
- No account, ever: nothing to sign up for. Just open the page and use it.
- No data stored: your files and the numbers you type are processed by your own browser. We never upload, store or see them.
- Works offline: once the page has loaded, most tools keep working without internet.
- Open source: anyone can read the code on GitHub.
Frequently asked questions
How is lump sum return calculated?
Future value = P × (1 + r)t, where P is the amount invested, r the expected annual return and t the number of years. ₹1 lakh at 12% for 10 years grows to about ₹3.1 lakh.
Lump sum or SIP: which is better?
If you already have the money and a long horizon, a lump sum has more time in the market. If markets look expensive or you invest from salary, a SIP spreads the risk. Many investors split the amount over a few months (an STP).
What return should I assume?
Use conservative figures: around 10–12% for diversified equity funds over the long term, 6–7.5% for debt funds and FDs. Past returns are not guaranteed.