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Glossary · Financial Portfolio

What is compound interest?

Compound interest is interest calculated on an amount that already includes earlier interest. The balance used for the next calculation grows when interest is added.

Plain English. Australian context.

Compound interest

Know what the term means, what it does not mean and where to go next.

Meaning & context

What it means for your records.

Plain-English information to help you organise your financial picture.

Financial Portfolio editorial team
Australian record-keeping context
Updated 7 October 2026

A simple example

With A$1,000 earning an illustrative 5% a year, compounded annually, the first year adds A$50. The second adds A$52.50, giving A$1,102.50. This assumes an unchanged rate, no deposits, withdrawals, fees or tax.

What to keep in your records

Keep the starting balance, interest rate, compounding frequency and statement date together. Label projections separately from actual balances so a forecast does not become a recorded asset value.

A common mix-up

A projected return is not a promise. Simple interest is calculated on the original amount, while compounding also takes previously added interest into account. Read ASIC Moneysmart’s explanation.

Is compound interest the same as investment growth?

No. Investments can change in value without paying interest. Compounding describes a calculation or reinvestment effect, not a guaranteed investment outcome.

Where can I check the meaning of compound interest?

Use the ASIC Moneysmart source alongside the relevant statement or product documents. The examples here explain the term; they do not recommend a financial product.

Start with what you have

Bring your financial life into focus.

You do not need every detail on day one. Start with the records that matter most, then build a clearer picture at your own pace.