Compound Interest Calculator
Project future value with compound interest and regular monthly contributions.
Project future value with compound interest and regular monthly contributions.
The Compound Interest Calculator projects how your money grows over time when interest is earned not only on the principal but also on previously accumulated interest. By factoring in regular monthly contributions and different compounding frequencies, it gives you a realistic picture of future wealth accumulation for any savings or investment plan.
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. Unlike simple interest, which only grows linearly, compound interest accelerates growth because each interest payment itself earns interest in subsequent periods. The more frequently interest compounds, monthly versus annually for example, the faster the balance grows. Albert Einstein reportedly called compound interest the eighth wonder of the world, and understanding it is fundamental to making informed saving and investing decisions. This free, browser-based calculator performs all computations locally on your device with no login or data sharing required.
Enter your initial principal, monthly contribution amount, annual interest rate, compounding frequency, and the investment time horizon in years. Click Calculate and the tool displays the projected future value, total contributions made, and total interest earned. A year-by-year breakdown table shows how the balance grows over time, making it easy to visualise the power of compounding. Adjust any input to explore different scenarios, such as increasing contributions or extending the time period, and see the impact instantly.