Split Loan Calculator
Model an Australian home loan split between fixed and variable portions, showing each split's repayment, the combined repayment and total interest paid.
Your results
Calculation breakdown
- Split check
- 50% + 50% = 100%
- Weighted starting rate
- (Fixed balance × fixed rate + variable balance × variable rate) ÷ total loan
Assumptions
- Each split is treated as its own principal and interest loan over the full loan term.
- Extra repayments are applied only to the variable portion, as is common practice.
- Fixed and variable rates are assumed constant for the projection.
How this calculator works
A split loan divides your mortgage into a fixed portion and a variable portion, giving you some repayment certainty on part of the loan while keeping the flexibility of extra repayments and features like an offset account on the rest. This calculator splits your total loan by the percentage you choose, treats each portion as its own principal and interest loan over the full term, and works out the repayment for each split at its own rate. It then combines them into a single overall repayment figure, a weighted starting rate across the whole loan, and a projected payoff timeline, with any extra repayments applied to the variable portion as is common lender practice. Splitting is a popular middle ground between fully fixing and staying fully variable, letting you hedge against rate rises on part of the loan while retaining flexibility on the rest — the right split percentage depends on your appetite for repayment certainty versus flexibility and how confident you feel about future rate movements.
Frequently asked questions
Why would someone split their home loan instead of fully fixing or staying fully variable?
A split lets you lock in repayment certainty on part of the loan while keeping flexibility, such as unlimited extra repayments and an offset account, on the variable portion — a middle ground for borrowers who want some of both.
Can I change my split percentage later?
Generally yes, most lenders allow you to adjust the fixed/variable split, though refixing usually only happens when the fixed portion's term ends or by refinancing, and may involve fees.
Why are extra repayments applied only to the variable portion here?
Fixed-rate loans commonly cap extra repayments during the fixed term and may charge break costs for early repayment, so extra repayments are typically directed to the variable portion, which this calculator reflects.
Results are estimates only and are not financial, tax, legal or credit advice.