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Compound interest calculator
See how a starting amount plus regular top-ups grows over time, and how much of the final balance is your money versus interest.
Leave at $0 for a plain lump sum. The frequency also sets how often interest compounds: for a term deposit, pick the one your bank pays interest at (check your term deposit's terms: many pay at maturity or annually).
Compounding is worked out at the frequency you choose, and interest is added before each top-up. Real returns vary and aren't guaranteed: this is an estimate to show the shape of growth, not a promise.
Enter a starting amount or a regular top-up to see how compound growth adds up over time. For example, $10,000 at 5% for 10 years grows to about $16,470.
Pure arithmetic on the numbers you enter. Amounts are in Australian dollars. Free, no ads, and it runs in your browser: what you type isn't sent to us unless you choose to share a result. Spotted a mistake? Let us know. In New Zealand? Use the NZ version.
Questions, answered
- How does compound interest work?
- Interest is added to your balance, and the next lot of interest is worked out on the bigger balance. Over long periods that interest on interest does most of the work, which is why starting early matters more than starting big.
- Are returns guaranteed?
- Bank interest rates are known in advance, but investment returns (shares, managed funds, super) vary year to year and can be negative. This shows a steady average rate to show the shape of growth, not a promise.
- Does it include tax?
- No. Interest and investment earnings are generally taxed as income in Australia, at your marginal rate, so real growth will be lower than shown.
- Is my data stored anywhere?
- No. It all runs in your browser. The only thing that touches our servers is the URL you create with 'Copy share link', which contains just the numbers you entered.