01 / Your figures
Build your growth estimate
Enter your starting amount, choose monthly or yearly contributions, set how long you will contribute, and choose the full maturity period.
See compounding accelerate
Your growth timeline
The table separates your own deposits from the estimated interest earned by each year-end.
| Year | Total deposited | Interest earned | Estimated balance |
|---|
Interest earns interest
The calculator converts the annual rate into a monthly equivalent and grows the balance month by month. Regular contributions can be monthly or yearly and can be added at the start or end of each contribution period. Contributions stop after the payment period you choose, while the accumulated balance can continue compounding until the later maturity date. With AER selected, the entered rate is treated as the effective annual return. With a nominal compounding option, the tool derives an equivalent monthly rate from the selected compounding frequency.
FV is future value, PV is the starting value, r is the periodic growth rate and n is the number of periods. Regular contributions are added separately during the selected contribution period, then the balance continues to compound until maturity.
Compound interest FAQs
Useful points to understand before relying on a long-term projection.
What is compound interest?
Compound interest is interest calculated on both the original amount and interest already added. Over time, that can make growth accelerate compared with simple interest.
What does AER mean?
AER means Annual Equivalent Rate. It is designed to show the annual return after allowing for compounding, which makes savings accounts with different payment frequencies easier to compare.
Does this calculator include tax?
No. The projection is before any tax, product fees or investment charges. Tax treatment depends on the account used and your circumstances.
Does monthly or daily compounding always mean a better return?
Not if you are comparing products using AER, because AER already incorporates compounding. Compounding frequency matters when the quoted rate is nominal rather than an effective annual rate.
Can I stop paying in before the investment matures?
Yes. Set a shorter contribution period and a longer maturity period. The calculator stops adding new money after the contribution period but continues compounding the balance until maturity.
Why is the final amount only an estimate?
The calculator assumes the selected rate continues for the whole term and that contributions are made consistently during the contribution period. Real savings and investment returns, fees and inflation can change.
Can I use this for investments?
You can use it as an illustration of regular compounded growth, but investment returns are not guaranteed and normally fluctuate rather than arriving at a fixed interest rate.