How an RBA Cash Rate Change Can Reach Your Monthly Repayment
When the Reserve Bank of Australia (RBA) adjusts the official cash rate, the effect is not a single, automatic line to your home loan. Instead, the change typically flows through the interest rates that lenders charge on variable home loans. For most residential mortgages, your monthly repayment is recalculated from the new interest rate, the remaining loan balance, and the remaining loan term.
A common assumption is that a 0.25 percentage-point move in the cash rate translates into a specific dollar change per month, but the actual impact varies with your loan size, how much you still owe, and the remaining years of the loan. Because every loan is different, it is more useful to look at a few worked examples than to rely on a one-size-fits-all figure.
Example Repayment Changes for Different Loan Amounts
The tables below show how a hypothetical 0.25 percentage-point increase in the cash rate might affect the monthly repayment on a variable-rate home loan with a 25-year remaining term. These figures are illustrative calculations, not a lender guarantee, and they assume the full rate change is passed on by the lender.
| Loan amount | Monthly repayment before a 0.25% rise | Monthly repayment after a 0.25% rise | Approximate increase per month |
|---|---|---|---|
| $400,000 | $2,168 | $2,228 | $60 |
| $600,000 | $3,252 | $3,342 | $90 |
| $800,000 | $4,336 | $4,456 | $120 |
| $1,000,000 | $5,420 | $5,570 | $150 |
These examples are based on an assumed starting interest rate of 5.50% per annum. They are provided to illustrate how the same rate change has a larger dollar effect on larger loan amounts, but they are not a projection of actual lender rates or mandatory repayment changes.
What This Means for Your Borrowing Plan
For anyone deciding how much to borrow, the key point from the worked examples is that a small change in the cash rate does not have the same monthly dollar impact for every borrower. A borrower with a $400,000 loan will see a smaller monthly increase than one with a $800,000 loan, even when the rate change is identical.
Also remember that the RBA cash rate decision is one input into your loan interest rate; lenders decide how much of any change to pass on and whether to adjust their own rates independently. If you are planning a home purchase, it is prudent to stress-test your budget against a potential rise in your monthly repayment, using your actual loan details and the latest lender information.
For a more tailored view of how a cash rate move could affect your repayments, you can speak with a mortgage broker who can model scenarios for your specific loan amount and term.