Compound Interest Calculator

Calculate how compounding grows your investments over time.

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10Yr
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Principal Amount
1,00,000
Total Interest
1,15,892
Total Amount
2,15,892
Principal
Compound Interest

Understanding the Compound Interest

What is Compound Interest?

Compound interest is the addition of interest to the principal sum of a loan or deposit. In other words, it is "interest on interest". Unlike simple interest, which only pays interest on the original amount, compound interest allows your money to grow exponentially because every time interest is credited, the new larger balance is used to calculate the next interest payment.

The Magic of Compounding Frequency

The frequency at which interest is compounded makes a massive difference. The more frequently interest is added to your account (e.g., daily or monthly instead of yearly), the faster your money grows. A 10% annual rate compounded daily will yield significantly more money after 20 years than the same 10% rate compounded annually.

The Rule of 72

The Rule of 72 is a simple mathematical trick to estimate how long it takes for your money to double at a given compound interest rate. Simply divide 72 by your annual interest rate. For example, if you are earning 8% per year, your money will double in approximately 9 years (72 / 8 = 9).

Frequently Asked Questions

Why is compound interest called the 8th wonder of the world?

Albert Einstein famously called compound interest the 8th wonder of the world because of its ability to exponentially multiply wealth over long periods of time. The longer you leave the money, the steeper the growth curve becomes.

How is it different from simple interest?

Simple interest is only calculated on the initial principal. Compound interest is calculated on the principal PLUS all previously accumulated interest.

Where do I earn compound interest?

You earn compound interest in almost all modern financial products, including Fixed Deposits (FDs), Public Provident Funds (PPF), Mutual Funds (via reinvested gains), and standard Savings Accounts.