How to use this Compound Interest calculator
Compound interest is often called the eighth wonder of finance because it pays you interest on your interest, turning patience into one of the most powerful forces in wealth-building. The same principle that grows your savings also inflates loan balances.
This calculator shows how a principal grows over time at a chosen rate and compounding frequency, making the gap between simple and compound growth impossible to ignore.
The compounding formula
The calculator uses amount = principal × (1 + rate ÷ n)^(n × years), where n is how many times interest compounds per year — annually, quarterly, monthly or daily.
Each compounding period adds interest to the balance, so future interest is earned on a progressively larger sum.
Frequency and the rule of 72
More frequent compounding produces a higher effective return at the same nominal rate, which is why daily compounding edges out annual.
A quick mental check is the rule of 72: divide 72 by the annual rate to estimate the years it takes your money to double.
Where it applies
Compounding drives savings accounts, fixed deposits, bonds and reinvested mutual-fund returns, and it also magnifies credit-card and loan balances if left unpaid.
Understanding it helps you start investing early and avoid letting high-interest debt compound against you.