Discover why Albert Einstein reportedly called compound interest the eighth wonder of the world and how it can build wealth over time.
Compound interest is the principle that allows your wealth to snowball over time. It's the reason why starting to save and invest early is far more important than the amount you initially save. It is the interest you earn on both your original money and on the interest you keep accumulating. To see this magic in action, try our Investment Calculator.
Simple vs. Compound Interest
To understand compound interest, you first need to understand simple interest. Simple interest is calculated only on the principal amount. If you invest ₹10,000 at 5% simple interest, you earn ₹500 every year.
Compound interest, on the other hand, is calculated on the principal amount and the accumulated interest of previous periods. In year one, you earn ₹500. In year two, you earn 5% on ₹10,500, which is ₹525. In year three, you earn 5% on ₹11,025, which is ₹551.25. The growth accelerates over time.
The Magic of Time
The true power of compounding is revealed over long periods. Let's look at an example comparing two investors:
- Investor A starts investing ₹5,000 a month at age 25. By age 35, they stop investing but leave the money to grow until age 60. (Total invested: ₹6,00,000)
- Investor B starts investing ₹5,000 a month at age 35 and continues until age 60. (Total invested: ₹15,00,000)
Assuming an 8% annual return, Investor A will actually have more money at age 60 than Investor B, despite investing significantly less money out of pocket. That is the power of giving your money a 10-year head start to compound.
The Rule of 72
A quick mental math trick to estimate compounding is the Rule of 72. It tells you approximately how many years it will take to double your money at a given interest rate.
Formula: Years to Double = 72 ÷ Interest Rate
If you expect a 6% return, your money will double in roughly 12 years (72 ÷ 6). If you expect a 9% return, it will double in 8 years (72 ÷ 9).
How to Maximize Compounding
- Start Early: The longer your money has to compound, the larger it will grow.
- Reinvest Your Earnings: Don't withdraw your interest or dividends; let them stay in the account to earn more.
- Compound More Frequently: Interest compounded daily or monthly will yield more than interest compounded annually.
- Be Consistent: Make regular contributions, no matter how small.
See the magic yourself with our Investment Calculator.