Should you refinance into a longer loan term?
Refinancing into a longer term can reduce the required repayment because principal is spread over more months. It can also increase total interest and leave more debt outstanding at your next review. Compare the new offer using your current remaining term first, then change only the proposed term. This separates the benefit of a different interest rate from the cost of taking longer to repay.
By Ratey · General information for Australian borrowers.
Example: $500,000 over 20 years or 30 years
Assume a current loan of $500,000 at 6.00% with 20 years remaining. Monthly principal-and-interest repayments are about $3,582. Refinancing at an illustrative 5.80% for the same 20 years reduces the repayment to about $3,525. Extending that new loan to 30 years reduces it further to about $2,934.
After five years, the same-term refinance owes about $423,088; the 30-year refinance owes about $464,107. The longer term requires around $591 less each month but leaves about $41,019 more debt at that point. Its first five years of interest are also about $5,562 higher.
Across the full schedule, the two new loans incur about $345,929 and $556,155 interest respectively. This example uses monthly calculations, constant rates, no fees, no offset and no extra payments. The roughly $210,226 lifetime gap isolates the term change; it is not a prediction of future rates.
Separate the rate decision from the term decision
Build three columns: stay with the current loan, refinance for the remaining term, and refinance for the longer term. Keep the new rate and fees identical in the last two columns. Now the difference between those columns comes from time rather than from a different offer.
Moneysmart cautions that a longer loan can mean more interest and recommends checking the term when switching. The useful question for your household is how much payment relief the longer term buys and what balance remains at the date you care about.
Look at a five-year balance as well as lifetime cost
A lifetime projection assumes you follow the schedule for decades. A shorter horizon can be easier to connect with your plans: a move, retirement, school costs or another mortgage review. Compare the amount paid, interest charged and debt outstanding at that same point.
A lower repayment lets you retain cash today. Some of that cash comes from repaying less principal. If you spend the difference, you will not have it available to offset the larger debt later. If you plan to save or repay it, write down that separate plan and check the account or loan conditions.
| Measure | How to use it |
|---|---|
| Required repayment | Check whether the payment fits your actual budget |
| Interest over the horizon | Measure the borrowing cost while you expect to hold the loan |
| Remaining balance | See the debt carried into the next stage |
| Scheduled end date | Check whether the obligation extends beyond your intended working years |
A plan to pay extra needs a second calculation
Choosing a longer contractual term and voluntarily keeping a higher payment is a different scenario from paying only the new minimum. Ask whether the product permits your intended extra repayments and how they are applied. A fixed-rate product may have restrictions or costs.
Use a repayment schedule for the amount you actually intend to pay. Do not attach the faster payoff of a higher-payment scenario to the monthly budget of the minimum-payment scenario. Both numbers need to describe the same behaviour. Keep the minimum-payment result visible so you understand what happens if extra payments stop.
If the reason is immediate budget pressure
Write down the monthly shortfall you are trying to solve and how long it may last. Compare the required reduction with the cost of the longer term. Ask your current lender about available options as well as obtaining a refinance quote; a new application still needs assessment.
If you are struggling with repayments now, contact the lender early and explain your circumstances. A calculator cannot determine which arrangement is suitable or whether another lender will approve it. Use the numbers as preparation for that discussion and avoid treating hoped-for future extra payments as certain.
Your next-step checklist
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Common questions
Does refinancing automatically restart a 30-year term?
The proposed term is part of the loan arrangement. Ask for the term you want and check the final contract rather than assuming the old remaining term carries over.
Can a lower rate still mean more lifetime interest?
Yes. A sufficiently longer repayment period can outweigh a lower rate. The example shows why comparing only the rate or required repayment misses this effect.
Is a longer term always a bad choice?
It can provide valuable cash-flow flexibility, but that comes with a cost if you follow the longer schedule. Assess the trade-off using a realistic budget and repayment plan.
Sources and assumptions
These primary sources support the explanations above. Examples use invented figures to show the calculation or decision; they are not available loan offers. Check your lender’s terms for your circumstances.
Calculations are estimates and do not establish borrowing eligibility. Read the calculation methodology.
Compare the two terms
Use the same-term refinance as your starting point, then inspect the longer-term scenario.