--- title: Split Loan Calculator | Fixed and Variable Split | GNT Finance description: Model a fixed and variable split on your Melbourne home loan. See repayments, what happens if variable rates rise or fall, and which split ratio suits you. url: https://gntfinance.com.au/calculators/split-loan/ section: calculators updated: 2026-09-01 author: Gorakh Timilsina, GNT Finance --- # Split loan calculator **In short:** This calculator shows your combined monthly repayment when part of your home loan is fixed and part is variable, and how that repayment changes if variable rates move. The rule of thumb: the fixed portion is your insurance against rate rises, the variable portion is where you keep your offset and make extra repayments. A 50/50 split halves your exposure either way. Splitting a loan is not about picking a winner between fixed and variable. It is about deciding how much rate certainty you want to buy and how much flexibility you want to keep. ## How this calculator works ### Two loans, one property A split loan is treated by the lender as two loan accounts secured by the same home. The calculator runs a separate amortisation for each portion: the fixed part at the fixed rate for its term, the variable part at the variable rate. Both use the standard repayment formula over the remaining term, and the results are added together to give your total monthly repayment. ### Rate scenarios You can set a change to the variable rate, for example plus 1.00% or minus 1.00%, and the calculator recalculates only the variable portion. That isolates what a split actually protects you from. ### Assumptions - Principal and interest repayments over 30 years on both portions unless you change the term. - The fixed rate applies for the whole fixed term and reverts to the variable rate afterward. - Extra repayments and offset apply to the variable portion only, which mirrors most lender products. - No break costs, rate lock fees or package fees are included unless you add them. ## How to use the result Read the "if rates rise" column first. That is the repayment you need to be able to afford in a bad year. If the fully variable figure under a 1% rise would strain the budget but the split figure would not, a split is doing its job. Then look at the "if rates fall" column to see what certainty costs you. The [fixed vs variable guide](/guides/fixed-vs-variable-rate/) explains the trade-offs in more depth, and the [RBA cash rate guide](/guides/rba-cash-rate-and-your-mortgage/) covers how variable rates actually move. ## Worked example A Greenvale family has a $600,000 loan over 30 years. For illustration, at 6.00% p.a. on both portions, they compare a 50/50 split with a fully variable loan under three rate paths. | Variable rate path | Fixed $300,000 (6.00%) | Variable $300,000 | Split total | Fully variable $600,000 | |---|---|---|---|---| | Variable stays at 6.00% | $1,799 | $1,799 | $3,597 | $3,597 | | Variable rises to 7.00% | $1,799 | $1,996 | $3,795 | $3,992 | | Variable falls to 5.00% | $1,799 | $1,610 | $3,409 | $3,221 | If rates rise by a full point, the split costs $197 a month less than going fully variable. If rates fall by a point, it costs $188 a month more. That symmetry is the point: you are trading upside for protection on half the loan. A 70/30 split (70% fixed) would narrow both figures further; a 30/70 split would widen them. ## What this calculator doesn't include - Break costs if you exit or refinance the fixed portion early. These can run into the tens of thousands in a falling-rate environment; read [breaking a fixed rate loan](/guides/breaking-a-fixed-rate-loan/) before you fix. - The revert rate at the end of the fixed term, which is often higher than the lender's best variable rate. - Caps on extra repayments during the fixed period, commonly $10,000 to $20,000 a year. ## Tips to improve the outcome - Fix the portion you know you will not pay down within the fixed term; keep the variable part sized to your realistic surplus and offset balance. - Match the fixed term to your plans. If you may sell, renovate or refinance in two years, avoid a five-year fix. - Use the [offset calculator](/calculators/offset/) to see how much of the variable portion your savings will neutralise; that changes the ideal split. - Compare lenders on both rates, not just the fixed headline. Use the [loan comparison calculator](/calculators/loan-comparison/) to test total cost. ## Frequently asked questions ### Should I split my home loan 50/50? A 50/50 split is the common starting point because it halves your exposure to rate rises while leaving half the loan free for offset and extra repayments. It is not a rule. If you have a large offset balance or expect to pay down quickly, weight toward variable. If your budget is tight and certainty matters more, weight toward fixed. ### Can I make extra repayments on a split loan? Yes, usually without limit on the variable portion. The fixed portion typically allows a capped amount per year, often between $10,000 and $20,000, and exceeding it can trigger break costs. Direct surplus cash and your offset to the variable account, and treat the fixed account as set and forget. ### Does a split loan have two repayments? You will see two loan accounts on your statement, each with its own repayment, rate and term. Most lenders let you set one direct debit that covers both. The calculator adds them together so you can budget on a single monthly figure. ### What happens when the fixed portion expires? The fixed portion reverts to the lender's standard variable rate, which is often higher than what new customers are offered. Around three months before expiry, ask your broker to compare re-fixing, repricing with the same lender or [refinancing](/services/refinancing/) the whole loan. Doing nothing is the most expensive option. ## Talk to GNT Finance Choosing a split ratio and fixed term is easier with someone who has watched hundreds of loans through rate cycles. GNT Finance can show you how different splits behave across lenders and lock in the structure that fits your plans, at no cost to you for our home-loan service in most cases. [Book a free consultation](/contact/) or call 0426 403 703.