Compound Interest Calculator
Starting investment amount
Expected annual return rate
Investment duration
How often interest is calculated
Additional monthly deposits
Results
Final Balance
Total Contributions
Interest Earned
How the Compound Interest Calculator Works
Compound interest grows your balance not just on your original principal, but on the interest it has already earned. This calculator applies your chosen compounding frequency (annual, monthly, daily, etc.) to your starting principal, and separately grows any regular monthly contributions you add along the way, then combines both into your final balance.
The more frequently interest compounds and the longer your time horizon, the bigger the gap between your total contributions and your final balance — that gap is the interest earned shown in your results.
Frequently Asked Questions
How does compounding frequency affect the result?
More frequent compounding (daily vs. annually) earns slightly more interest on the same rate, because interest starts earning its own interest sooner.
When are monthly contributions added?
Contributions are treated as being made at the end of each period and grow at your chosen compounding frequency for the remaining time.
Does this account for inflation?
No — this shows nominal growth. Use the Inflation Impact Calculator alongside it to see what your future balance is worth in today's purchasing power.