Compound Interest Calculator
Calculate how your investment grows over time with compound interest and regular contributions.
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Understanding Compound Interest
Compound interest is one of the most powerful forces in finance. Albert Einstein reportedly called it the "eighth wonder of the world" — and for good reason. When your investments earn returns that themselves earn returns, wealth can grow exponentially rather than linearly.
The key variables are: your initial capital (the lump sum you start with), your monthly contributions (regular additions that amplify the compounding effect), the annual interest rate (expected return on investment), the time horizon (the longer the better), and the compounding frequency (how often interest is calculated and added back to the principal).
This calculator supports monthly, annual and daily compounding. For most retail investors tracking ETFs or index funds, monthly compounding closely reflects real-world reinvestment behaviour. The visual chart shows how your balance splits between contributed capital and interest earned — making the power of compounding easy to visualise.