How Compound Interest Works
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. Unlike simple interest, which only earns interest on your original deposit, compound interest lets your money grow exponentially over time.
The formula used is: A = P(1 + r/n)nt, where P is the principal, r is the annual rate, n is the compounding frequency, and t is the number of years. When you make regular monthly contributions, the calculator adds those to each compounding period.
Why Compounding Frequency Matters
The more frequently your interest compounds, the faster your money grows. Daily compounding earns slightly more than monthly, which earns more than annually. For most savings accounts and investments, monthly or daily compounding is standard.
Tips to Maximise Compound Interest
- Start early — even small amounts grow significantly over decades.
- Contribute consistently — regular monthly deposits accelerate growth.
- Reinvest returns — let dividends and interest compound rather than withdrawing them.
- Compare rates — even a 0.5% higher rate makes a large difference over 20+ years.
Who Should Use This Calculator?
This calculator is useful for anyone planning long-term savings, retirement investing, or comparing fixed-deposit products across different banks and countries. Whether you are saving in dollars, euros, rupees, or any other currency, the mathematics of compounding works the same way everywhere.