Lumpsum Calculator

While a SIP (Systematic Investment Plan) requires you to add money every month, a Lumpsum investment relies entirely on the pure exponential curve of a single initial deposit.

This calculator uses the standard future value formula: FV = P(1+r)^t to show you exact, penny-perfect results over any time period.

While calculators are great, there is a legendary mental math shortcut you can use when you're away from a computer. It's called the Rule of 72.

If you want to know exactly how many years it will take to double a lumpsum investment, simply divide the number 72 by your expected annual interest rate.

• If your mutual fund returns 12%: 72 / 12 = 6 years to double.
• If your Fixed Deposit returns 6%: 72 / 6 = 12 years to double.
• If your savings account returns 4%: 72 / 4 = 18 years to double.

This isn't just a random guess; it is a mathematically proven approximation derived from natural logarithms. Specifically, it comes from the Taylor Series expansion of ln(1+r).

Try entering a 12% return into the calculator above and look at the chart at Year 6—you will see your initial investment has exactly doubled!