Quick answer: A lower rate is not automatically a cheaper refinance. Compare dollar savings over the period you expect to keep the new loan, subtract switching costs, and avoid extending debt merely to reduce repayments.
The refinance decision: compare three paths, not two
A mortgage rate advertisement is not a refinance outcome. The real decision is whether to stay on your current rate, negotiate a repricing with your existing lender, or switch lenders. Each option can have a different required repayment, balance remaining after several years, annual package cost and cash cost of the transaction.
The Refinance Break-Even Calculator models these three options over the same holding period.
What you need for a credible comparison
| Input | Why it matters |
|---|---|
| Current outstanding balance | The rate saving applies to a declining principal balance |
| Existing rate and years remaining | Sets the original scheduled repayment and future balance |
| Proposed rate and new term | A lower monthly repayment may just be a longer term |
| Switching costs | Discharge, application, registration, legal and any applicable fixed-rate break cost |
| Cashback | An incentive received once, not a recurring interest saving |
| Current and proposed offset | Different interest-bearing balances can outweigh a headline rate gap |
| Annual/package fees | Small recurring charges accumulate over several years |
| Expected holding period | Selling or refinancing again in two years differs from staying ten years |
| Possible lender repricing | You might improve the interest rate without moving lenders |
Compare total repayments made + mortgage balance remaining + fees − any cashback at the same future date. This keeps a lower scheduled payment from looking better merely because less principal was repaid.
Worked example: $650,000 owing, 22 years remaining
Assume the current rate is 6.25% and another lender offers 5.85%, with $1,200 total switching costs. Keep the remaining 22-year term and assume five years before the next review, no offset and unchanged rates.
- The current scheduled principal-and-interest repayment is approximately $4,537 per month.
- The replacement mortgage's scheduled repayment is about $4,383 per month.
- Over five years, the model estimates an $11,569 economic advantage after switching costs, reflecting the interest, fees and remaining balance—not just cash-flow relief.
- The illustrative economic break-even occurs around month six.
These are controlled scenario outputs. They are not current lender offers, forecasts or a representation of daily accrual under an actual product.
Worked example: why a 30-year reset changes the answer
Keep the $650,000 balance and 5.85% replacement rate, but reset the term from 22 remaining years to 30 years. The minimum monthly repayment falls to approximately $3,835. That feels like more breathing room.
However, after five years the new mortgage would have about $34,553 more debt outstanding than the otherwise identical 22-year refinance path under the same assumptions. You may welcome the monthly flexibility, but do not describe the lower repayment as equivalent to a $548 monthly interest saving. It is substantially a change in how quickly principal is repaid.
If you do choose a longer contractual term, calculate the effect of making voluntary extra payments to keep the principal-repayment trajectory closer to the original loan.
When is a small rate cut worth switching?
The annual interest difference at today's balance is a starting illustration, not a break-even calculation. A 0.20% difference on $800,000 initially corresponds to $1,600 a year before the balance falls; the same gap on $180,000 initially corresponds to $360 a year. If switching costs are $2,000, the smaller-balance borrower needs more time to overcome those costs.
Change the borrowing balance, remaining term, rate gap and fees in the calculator. Do not rely on a blanket rule that switching is worthwhile only at a particular number of basis points.
Is a cashback offer genuinely cheaper?
Cashback can reimburse some upfront costs, but the lender may have a higher rate, different package costs, minimum balance requirements or a limited eligibility window. Model the incentive as a once-only cash receipt and compare the interest and fees through your likely holding date.
A $3,000 cashback doesn't by itself prove a refinance is worth $3,000. Nor should any rebate be assumed unless it's a genuine feature of an available offer for which you're eligible.
Should you negotiate the rate with your current bank first?
Often that's the lowest-friction alternative. A repricing may avoid some discharge, registration and establishment charges. The counteroffer still needs to be compared with the proposed new loan's rate and features.
In the calculator's advanced section, enter the rate your existing lender might offer and any repricing fee. Compare the benefit with doing nothing, then compare it with the net result of switching. If the bank won't improve its pricing, the third scenario makes the value of other lenders easier to explain.
Offset balances can overturn a simple rate comparison
An eligible offset generally reduces interest charged on the linked mortgage while keeping the money available. A product with a headline interest rate 0.10% lower may be less attractive if it loses an offset facility you actively use or adds a high package fee.
Compare the average offset amount, not a one-day peak balance. An offset balance that moves from $100,000 after payday to almost zero before bills is not economically equivalent to a stable $100,000 balance. The calculator uses user-selected constant offset assumptions; real lenders often accrue interest daily.
What if I expect to sell or refinance again soon?
Holding period is a central variable. Fees incurred now may never be recovered if you sell or refinance again in a short period. Test 12, 24, 36 and 60 months instead of picking an arbitrary 30-year lifetime comparison. If you expect a fixed rate to expire or a property sale, include those dates as meaningful decision points.
Questions Australian borrowers actually ask
Should I refinance for a 0.25% discount?
Possibly. On a large remaining balance and with low fees, a small reduction can matter. On a small balance with higher switching costs, it may not. Calculate dollar savings over your real holding period.
Is refinancing worth it when I owe less than $250,000?
It depends on fees, term, interest rate, package costs and how long the new loan remains in place. A small balance can make the fixed costs more significant relative to interest saved.
Does lowering my repayment mean I'm saving interest?
Not necessarily. A new 30-year schedule can reduce the monthly obligation while increasing the debt left after five years. Compare equal-horizon interest, fees and outstanding principal.
Does an existing lender have to match a competitor?
No. A competitor quote or documented pricing offer creates a useful negotiation benchmark, but the current lender may refuse to match it. Model both outcomes.
What if my employment changed since the original home loan?
A new lender reassesses current income and other credit criteria. A rate reduction with the existing lender can involve a different process from a full refinance application. The financial model and lender eligibility are distinct questions.
Can I refinance to release equity and consolidate debts?
That changes the amount and purpose of the debt, not just the interest rate. Compare the larger resulting mortgage and how long the consolidated portion takes to repay. Read equity release and cash-out refinancing.
Compare before you enquire
Use the Refinance Break-Even Calculator to compare the current mortgage, new lender and negotiated repricing. Then explore mortgage repayments and amortisation and the Home Loans Knowledge Centre.
A better rate is only the beginning. GPS Finance uses intelligent lender matching, negotiation and experienced credit judgement to help borrowers weigh the actual financing structure.
What if I reset to 30 years but keep the difference in offset?
The contract term sets the minimum repayment. Actual interest follows the interest-bearing balance over time. If the payment reduction stays in a fully effective offset, you need to compare debt less offset cash as well as the contractual balance. Spending that difference creates a different result.
Our 30-year refinance and offset example compares minimum payments, matching total cash flow and cash retained. Before settlement, also confirm how available redraw will be treated.
Sources and verification
- Moneysmart — Switching home loans
- Moneysmart — Mortgage offset accounts
- APRA — Macroprudential policy settings
These sources support the general mechanics and decision framework. Product availability, pricing, fees and lender policy can change. Tax-sensitive decisions should be checked against current ATO guidance and, where appropriate, a qualified tax adviser or accountant.
Related GPS Finance resources
- Reprice or Refinance Your Home Loan?
- Offset vs Redraw: Which Is Better for Flexibility, Tax and Future Plans?
- Fixed, Variable or Split Home Loan? Structure the Loan Around Your Cash Flow
- Mortgage options
- Refinance Break-Even Calculator
About the author: Krish Neelamraju is a finance and credit professional and founder of GPS Finance Group.
General information only. It is not personal financial, tax or legal advice. Finance approval, pricing, terms and structure are subject to lender assessment and the borrower’s circumstances.
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