A projection shows what happens if the assumptions hold. Real life can change.
- Money you put in
- $10,000
- Modelled interest
- $1,000
- Example ending balance
- $11,000
Illustrative breakdown only, not a rate or return forecast.
Change one thing at a time
A projection is easiest to understand when only one input changes. Keep the starting balance, rate and timeframe fixed while trying a different deposit amount. Then return to the original contribution and vary the rate. If every number changes at once, you cannot easily tell which decision produced the difference.
Check what the end balance contains
If you start with $10,000 and add $500 per month for ten years, your own deposits total $70,000 before any interest. A future balance above that includes the modelled interest. When someone compares two accounts using only the final balance, it can hide the fact that most of the money comes from consistent saving rather than the rate difference.
Look for assumptions about timing
An annual interest rate does not specify when money is credited. A projection might compound yearly, monthly or daily, and contributions might arrive at the beginning or end of a period. Howloop’s savings calculators use monthly compounding and end-of-month contributions. This makes the method reproducible, but it is not an exact reconstruction of bank interest.
Allow for rates to change
A variable bank rate can move during a multi-year plan. A welcome offer may last only a few months. Test a lower constant rate as a sensitivity check, and separately calculate a short introductory period if you want to understand it. Do not use a temporary promotional rate as though it were guaranteed for ten years.
Use three scenarios with the same deposits
Take the $10,000 starting balance and $500 monthly deposits over ten years. With monthly compounding and end-of-month deposits, hypothetical constant annual rates of 3%, 4.5% and 6% produce about $83,364, $91,269 and $100,134 respectively. Your deposits remain $70,000 in every case; the modelled interest is about $13,364, $21,269 and $30,134. The middle figure is not the most likely forecast, and the other two are not statistical confidence limits. They simply show what these three chosen assumptions would produce. Actual rates could fall outside them.
Reconcile a row before relying on the total
Each year-end row combines the opening balance, accumulated deposits and accumulated interest. For the example above, total deposits after year one should be $16,000: the initial $10,000 plus twelve payments of $500. After year five they should be $40,000. At 0% interest, the closing balance should equal the deposit total. These checks can catch an incorrect starting amount or payment frequency before you spend time interpreting a graph. Interest shown in a year-end row is cumulative from the start, not necessarily the interest earned in that one year.
Find the cause of a difference between calculators
Write the inputs beside each result: opening balance, contribution amount, contribution frequency, annual rate, years, compounding frequency and deposit timing. If one calculator uses actual weekly payments and another converts them to monthly averages, matching the visible rate and dollar inputs is not enough. Compare both at 0% first to reconcile total deposits. Then use a zero-contribution run to isolate the compounding convention. Finally restore the deposits. This sequence helps identify a timing difference without assuming that the larger result is the more accurate one.
Keep the calculation separate from purchasing power
A dollar target can be reached while the item it was meant to buy becomes more expensive. To see the arithmetic, suppose an item costs $80,000 today and its price rises by a purely hypothetical 3% each year for five years. Its price would be about $92,742 at the end of that period. This is not an inflation forecast or a claim about any specific purchase. Howloop displays future dollar balances and does not automatically raise your target, so update the target separately when you review actual expected costs.
Leave a trail for the next review
Save the input amounts, the date and why you chose the rate. Export the year table if you want to compare it with a later run. Howloop's optional saved scenario stays in the browser on that device; it is not a bank record or an account synced across devices. At your next review, begin with the money actually available and the time still remaining. Keep the old projection for comparison, but do not add interest from the old forecast to a current balance that already includes interest.
Remember what is outside the number
The balance is nominal Australian dollars. It does not include inflation, tax, fees, withdrawals or changes to your income. The result therefore cannot tell you the future purchasing power of the money or the after-tax benefit of choosing one product. Use the year-by-year table to understand the calculation, and check the actual account documentation before acting.
What is a useful way to test a savings plan?
Sources & update record
Added a short explanation, simple example and knowledge check; retained the detailed guide and source record.
Published 18 Sept 2026 · Updated 18 Sept 2026. These dates do not guarantee rules are unchanged.
Published by Howloop. AI assists preparation. This lesson has not been reviewed by a licensed financial adviser. How we check our content →