Disclaimer: This calculator provides estimates only and should not be considered financial or investment advice. Results assume a constant interest rate which will differ from actual investment returns. Interest earned may be subject to income tax. Evercend Pty Limited does not hold an Australian Financial Services Licence.
Compound interest calculator inputs and results
Enter your details to see results
Add an initial deposit or regular contribution, an annual interest rate and an investment period to see how your money grows.
How compound interest works
Compound interest is interest earned on both the starting balance (the principal) and on interest already earned, so the balance can grow faster over time. This is different from simple interest, which applies only to the starting amount. Some term deposits use simple interest.
How this calculator works
The calculator estimates a future balance from a starting amount, an interest rate, a time period, a compounding frequency and any regular deposits. The standard compound interest formula is A = P(1 + r/n)^(nt), where A is the ending balance, P is the principal, r is the annual interest rate as a decimal, n is the number of times interest is added each year, and t is the number of years. ASIC MoneySmart presents the same relationship as A = P x (1 + r)^n, applying the periodic rate over the number of periods.
Assumptions used
Results are estimates only and actual amounts may be higher or lower. Results are shown in future dollars with no adjustment for inflation, so their real spending power will be lower. Regular deposits are assumed to be made at the end of each period, and interest is assumed to be credited in line with the compounding frequency selected. The calculator does not account for tax on interest or for account fees.
Worked example
Putting $10,000 into an account paying 3% interest compounded monthly grows to about $11,616 after 5 years ($1,616 in interest), about $13,494 after 10 years ($3,494 in interest) and about $18,208 after 20 years ($8,208 in interest). This shows how the interest earned each year increases as the balance grows.
Two people each invest $10,000 at 5% for 5 years. One earns interest monthly and ends with about $12,834; the other earns interest only at the end of the 5-year term and ends with $12,500. The monthly compounding earns about $334 more, because interest is earned on interest more often.
The calculator applies your actual inputs to show the year-by-year breakdown.
What changes your compound interest result
Several things change the final balance when interest compounds over time. The main ones are:
Time in the account
A longer period gives more compounding periods, so the balance has more opportunities to grow.
Interest rate
A higher rate increases the amount of interest added each period.
Compounding frequency
More frequent compounding adds interest to the balance sooner, so interest starts earning interest earlier.
Regular deposits
The size and frequency of deposits added to the balance during the period.
Inflation
Reduces the real value of the future balance, which the calculator does not model.
Tax and fees
Tax on interest and account fees would both reduce the actual balance; the calculator does not model either.
Rates and assumptions used
| Item | Value used | Source |
|---|---|---|
| Compound interest formula | A = P(1 + r/n)^(nt) | ASIC MoneySmart, Compound interest |
| Calculator assumptions (future dollars, no inflation adjustment, end-of-period deposits) | Results are estimates in future dollars; no tax or fee adjustment | ASIC MoneySmart, Compound interest calculator |
Figures checked against the sources above on 10 August 2026.
Frequently asked questions
Simple interest is calculated only on the starting amount, while compound interest is calculated on the starting amount plus interest already earned, so the balance can grow faster.
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Sources
Content reviewed and figures checked against the sources above on 10 August 2026.