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Split Loan Calculator Australia — FY 2025-26

A split loan calculator Australia helps borrowers compare the costs and benefits of dividing their home loan into fixed and variable rate portions.

People Also Ask

A split loan divides your mortgage into two accounts, one with a fixed interest rate and one with a variable rate. You choose the proportion allocated to each portion based on your preference for rate certainty versus flexibility.
A split loan offers the rate security of a fixed rate on part of your loan while retaining flexible features such as extra repayments, redraw, and offset accounts on the variable portion. This balances risk and flexibility.
Most lenders allow you to adjust the split ratio at the end of the fixed-rate period. During the fixed period, changes are generally not permitted or may incur break costs and fees.
Split loans typically have the same ongoing fees as standard variable loans, though there may be a small administration fee for maintaining two loan accounts. Compare total costs including annual fees before choosing.
4 min readLast updated: 2026-05-26

About the Split Loan Calculator

A split loan calculator Australia helps borrowers compare the costs and benefits of dividing their home loan into fixed and variable rate portions. Split loans are a popular strategy among Australian homeowners who want the stability of fixed rates with the flexibility of variable features. This tool helps you find the optimal split ratio for your financial situation.


What is the Split Loan Calculator?

This calculator models how splitting a home loan into two portions affects your total repayments, interest costs, and loan term. A split loan divides the total loan amount into a fixed-rate portion and a variable-rate portion, typically expressed as percentages such as 60/40 or 70/30. The fixed portion locks in an interest rate for a set period, usually 1 to 5 years, protecting against rate rises. The variable portion offers features such as unlimited extra repayments, redraw facility, and an offset account. The calculator compares the total interest payable, monthly repayments, and overall cost under different split scenarios. It also compares a fully variable loan and a fully fixed loan against your chosen split option. Australian borrowers use this tool to decide on the best loan structure when refinancing or taking out a new mortgage. By adjusting the split percentage and interest rates, you can see how different market conditions affect your total cost and find the balance that suits your risk tolerance and financial goals.


How to Use This Calculator

  1. 1Enter the total loan amount: Input the total mortgage amount you plan to borrow.
  2. 2Enter the split percentage for fixed portion: Input the percentage of the loan you want on a fixed rate.
  3. 3Enter the fixed interest rate: Input the fixed rate offered by your lender for the chosen fixed period.
  4. 4Enter the variable interest rate: Input the current variable rate for the remaining loan portion.
  5. 5Enter the loan term: Input the total loan term in years, typically 25 or 30 years.
  6. 6Select the fixed period: Choose how many years the fixed portion will remain fixed before reverting to variable.
  7. 7Review your comparison: The calculator shows split loan repayments, total interest versus fully variable and fully fixed alternatives.

Worked Australian Example

Practical Example

Emma and Tom are refinancing their home in Adelaide, SA with a total loan of $450,000. They want to split their loan with 60% fixed and 40% variable. The fixed rate is 5.9% for 3 years and the variable rate is 6.4%. The loan term is 30 years. Using the calculator, they enter $450,000 as the total loan, 60% fixed ($270,000), 40% variable ($180,000), 5.9% fixed, 6.4% variable, 30 years, and a 3-year fixed period. The calculator shows the split loan monthly repayment is $2,687. A fully variable loan at 6.4% would cost $2,814 per month, and a fully fixed loan at 5.9% would cost $2,661 per month. Over 3 years, the split loan saves approximately $4,572 compared to fully variable, while maintaining redraw and extra repayment flexibility on the variable portion. Emma and Tom choose the 60/40 split, valuing both the rate security and the flexibility of an offset account linked to the variable portion.


Common Split Loan Calculator Questions

A split loan divides your mortgage into two accounts, one with a fixed interest rate and one with a variable rate. You choose the proportion allocated to each portion based on your preference for rate certainty versus flexibility.
A split loan offers the rate security of a fixed rate on part of your loan while retaining flexible features such as extra repayments, redraw, and offset accounts on the variable portion. This balances risk and flexibility.
Most lenders allow you to adjust the split ratio at the end of the fixed-rate period. During the fixed period, changes are generally not permitted or may incur break costs and fees.
Split loans typically have the same ongoing fees as standard variable loans, though there may be a small administration fee for maintaining two loan accounts. Compare total costs including annual fees before choosing.
The right split depends on your risk tolerance and financial goals. A common starting point is 60% fixed and 40% variable, but this varies based on interest rate outlook, your cash flow needs, and desire for repayment flexibility.


Reviewed by

BizMetrixs Team

Australian Financial Specialists

This Split Loan Calculator Australia calculator provides estimates only. Results are based on ATO 2025-26 published rates and general calculation methods. Individual circumstances may vary. This tool is for informational and educational purposes only and does not constitute financial, tax, or legal advice. For personalised advice, consult a registered tax agent or financial adviser.