Mortgage Switching Calculator

If you are paying more than the going rate on your home loan, switching to a sharper deal could save you thousands over the years you keep the loan. Use this mortgage switching calculator to estimate the difference between your current loan and a new one, after the switching costs, so you can see the real net saving rather than just a headline rate cut. Whether you are weighing up a refinance to chase a lower rate or simply checking whether it is worth the paperwork, the tool below gives you a number to start from.

How to use the Mortgage Switching Calculator

  1. Enter your current loan balance and remaining term. Use the amount you still owe, not the original loan, and how many years are left to run.
  2. Enter your current interest rate. The rate you are paying right now on the loan you are thinking of leaving.
  3. Enter current ongoing fees. The fees that you are paying right now.
  4. Enter the End Fee. This is the discharge fee charged by your existing lender when you discharge your mortgage. It is typically $300 to $500. 
  5. Enter the new rate. This switching tool asks for both an introductory rate (or fixed rate) and the standard rate it reverts to. Use current illustrative rates as a starting point, then confirm the real numbers with a broker.
  6. Add the Upfront Refinance Fees. The application or establishment fee on the new loan, plus the government registration fees. You can find the government registration fees in the Stamp Duty Calculator (the Mortgage Registration Fee X 2). Leave fixed-rate break costs out for now, because those need an actual figure from your lender.
  7. Review the result. The calculator shows your new repayment, the savings over the remaining term, and the additional savings you could make by making extra repayments. The bar chart shows the accumulated savings each year of the loan term. 

Switching and refinancing mean the same thing here: moving your home loan to a better deal, either with a new lender or your current one.

Worked example: switching a $500,000 loan to a lower rate

Infographic comparing a 500000 dollar home loan at 6.50 percent versus 5.99 percent showing the switching cost, break-even and net three-year saving

Take a $500,000 home loan with 25 years left to run. Here is what switching from an illustrative 6.50% to 5.99% looks like once the costs are in.

The repayment drop

At 6.50%, the repayment is about $3,376 a month. Drop the rate to 5.99%, and it falls to about $3,218, roughly $158 less every month. That is the cash-flow side: $158 back in your pocket each month for doing the paperwork once.

The interest saved

The bigger number is the interest. In the first year alone, the lower rate saves about $2,550 in interest on a $500,000 balance. Over three years, the gross interest saving comes to around $7,600, worked out on a reducing balance at the two rates.

The cost of switching

On a variable loan, the costs are modest. Say a $350 discharge fee on the old loan, a $200 application fee on the new one, and government registration fees totalling $351.40 in New South Wales. About $901 all up. Subtract that from the three-year interest savings, and you are left with a net saving of roughly $6,700 over three years. The $901 is recovered in about five months, and everything after that is yours.

Break costs scare people off, but on a variable loan, there usually are not any. The only real costs are a small discharge fee, government registration fees and the new lender’s setup fee. What actually matters is the rate gap multiplied by your balance over the years you keep the loan. On a $500,000 balance, half a per cent is real money. A broker also checks whether a sharp new rate survives once any introductory period ends, and whether a cashback offer tips the maths further in your favour.

Rates shown are illustrative only and current as at June 2026; your actual rates will depend on your lender, loan size and profile.

It is the same core maths the government’s own MoneySmart mortgage switching calculator uses, so the tool above gives you an independent view rather than a single bank’s pitch. CommBank, ANZ and Westpac each run their own refinance calculator, and NAB has its own home loan calculators, but a bank’s tool models a switch to that bank, not the genuine market-wide savings a broker can find.

What this calculator can’t tell you

The calculator compares two rates you type in. A real switch has moving parts it cannot see:

  • Fixed-rate break costs. If your current loan is fixed, leaving it early can trigger a break cost. The lender works it out from how rates have moved since you fixed and how much fixed term is left, so it can be large or close to nothing. The calculator cannot predict it, and a broker gets the actual figure from your lender before you commit. If you are weighing this up, see should I fix my home loan.
  • Whether the new rate lasts. Some sharp advertised rates are introductory or honeymoon rates that step up to a higher ongoing rate after a year or two. The calculator compares the rate you enter, but it does not know if that rate sticks. A broker models the revert rate, not just the teaser.
  • Cashback offers. Some lenders pay $2,000 to $4,000 or more to refinance to them, though these days the offers come mostly from smaller and mutual lenders rather than the big four. A cashback only helps if the ongoing rate is genuinely competitive; paired with a higher rate it can cost you more over a few years. The calculator ignores cashbacks entirely. See cashback offers for the catch.
  • Headline rate versus comparison rate. The headline rate is not the true cost. The comparison rate rolls the interest rate together with most fees and charges into a single figure, and switching to a lower headline rate that carries a worse comparison rate can leave you behind.
  • Whether you will actually qualify. Refinancing is a fresh loan application. Your servicing, loan-to-value ratio, LMI (if you have slipped above 80% LVR), and credit conduct all get re-assessed. APRA-regulated lenders test you at your new rate plus 3% (with some exceptions), so a switch that obviously saves money can still be knocked back on paper. A valuation fee, and rarely stamp duty, can also apply on top of the discharge and application fees. A broker checks you qualify before you pay anything.
  • Pricing across every lender. The calculator compares two rates. A broker compares your loan against the live pricing of more than 50 lenders, cashbacks and all, to find the genuine best switch, not just one bank’s number.

The calculator is your starting point. A broker models your real switching benefit across more than 50 lenders, break costs, revert rates and cashbacks included, so the saving on screen is the saving you actually pocket.

FAQs

Not sure? Have additional questions? Try here 

Enter your current loan balance, remaining term and interest rate, then the new rate you are considering and the switching costs (a discharge fee plus the new lender’s setup fee). The calculator estimates your new repayment, the saving over the remaining term, and how quickly the switching costs are recovered.

Often yes. On a $500,000 balance, a 0.50% lower rate saves roughly $2,500 in interest in the first year alone, while switching costs on a variable loan are usually only a few hundred dollars. The saving normally recovers the cost within a few months, then keeps adding up for the life of the loan.

On a variable loan, usually just a discharge fee on your current loan (commonly a few hundred dollars) and an application or establishment fee on the new one. A valuation fee can apply too. Fixed loans can also carry a break cost, which the lender calculates. A broker gets your exact figures before you commit.

A break cost is a fee for leaving a fixed-rate loan early. It depends on how interest rates have moved since you fixed and how much of your fixed term is left, so it can be large or close to nothing. Break costs do not apply to variable-rate loans.

Not always. Some sharp advertised rates are introductory or honeymoon rates that revert to a higher ongoing rate after one to two years. Before you switch, check the rate the loan reverts to, not just the headline rate. A broker models the revert rate so you are not caught out.

They can, but a cashback is only a win if the ongoing rate is genuinely competitive. A $3,000 cashback paired with a higher ongoing rate can cost you more over a few years than a smaller cashback with a sharper rate. Most cashbacks now come from smaller and mutual lenders rather than the big four. A broker weighs the cashback against the comparison rate.

Yes. A broker compares your current loan against the live pricing of more than 50 lenders, factors in break costs, revert rates and cashbacks, and handles the switching paperwork. Talk to a broker today.

This article contains general information only and does not constitute financial advice. Your personal financial situation, objectives and needs have not been considered. Before acting on any information, you should consider its appropriateness to your circumstances. Speak to a qualified mortgage broker for advice tailored to your situation. Mortgage World Australia Pty Ltd is a credit representative (CR No. 396946) of Mortgage Specialists Pty Ltd (Australian Credit Licence No. 387025).