Compound Interest Calculator
Compound interest is interest earned on interest — the reason long-term investing works. Enter your starting balance, rate and time horizon to see how much your money can grow, with or without regular monthly contributions.
How to use
- Enter your initial deposit or investment amount.
- Enter the expected annual return rate (e.g. 7 for 7%).
- Set the number of years and how often interest compounds (monthly, quarterly or yearly).
- Optionally add a monthly contribution to see the effect of regular investing.
Frequently asked questions
What is the difference between simple and compound interest?
Simple interest is earned only on the original principal. Compound interest is earned on the principal plus all accumulated interest, so growth accelerates over time.
How often should interest compound?
The more frequent, the better for the saver. Monthly compounding beats annual compounding at the same nominal rate, though the difference is modest at typical rates.
Does this account for inflation or taxes?
No — the result is in nominal terms. For a rough inflation-adjusted estimate, use a rate equal to your nominal rate minus expected inflation (e.g. 7% − 3% = 4%).