Compound Interest

This tool projects how a one-time principal grows under compound interest at a fixed annual rate, compounded at one of five frequencies. It returns the final amount, the total interest earned, a year-by-year balance breakdown, and a bar chart visualizing the balance at the end of each year. Calculations update live as you change any input.

1. Enter Principal (the starting amount, e.g. 10000). 2. Enter Annual Rate as a percentage (e.g. 5 for 5%). 3. Enter Years (1 to 100). 4. Pick a compounding Frequency button: Annually (1), Semi-annually (2), Quarterly (4), Monthly (12), or Daily (365). 5. Read the result cards: Final Amount, Total Interest, a per-year Growth Chart, and a Year-by-Year table showing balance, interest earned that year, and cumulative earned. Tap any value to copy it. Use Reset to clear all fields.

Final Amount = Principal * (1 + r / n) ^ (n * Years), where r is the annual rate divided by 100 and n is the compounding frequency (1, 2, 4, 12, or 365). Total Interest = Final Amount - Principal. The year-by-year balance for year y is Principal * (1 + r / n) ^ (n * y); interest for year y is the balance at year y minus the balance at year y-1; cumulative earned is balance at year y minus Principal. All money values are rounded to two decimals.