What is the best split ratio?

There's no perfect ratio - it depends on your circumstances. If you have significant savings for extra repayments, a larger variable portion makes sense. If budget certainty is your priority, lean towards more fixed.

Can I change the split later?

You can typically add to the variable portion anytime. Changing the fixed portion requires waiting until the fixed period ends or paying break costs. Some lenders allow internal refinancing between portions.

Do I get two separate loans?

Technically yes - a split loan creates two loan accounts under one facility. Each has its own repayment, rate, and features. Some lenders allow different offset accounts for each.

§ Tool · tier 1 · independent

Split Loan Calculator.

Calculate the optimal split between fixed and variable portions of your home loan

CalculatorFree, no signupOn-deviceupd May 2026

Inputs

Your numbers

Awaiting inputs

Move the sliders or type in the form on the left — the math updates live as you go. Click Get AI verdict when you want a written analysis.

A split loan gives you the best of both worlds - the certainty of a fixed rate on part of your loan, plus the flexibility of a variable rate on the rest. Use our calculator to find the right split ratio for your needs.

§ Worked examples

Real-world scenarios

Conservative First Home Buyer

Lisa has a $550,000 loan, wants budget certainty but also flexibility. Fixed 5.8%, variable 6.2%.

Inputs

loanAmount:550,000loanTerm:30fixedRate:5.8fixedTerm:2variableRate:6.2splitRatio:70

70/30 split: $385,000 fixed at $2,262/month (stable), $165,000 variable at $1,004/month (flexible for extra payments).

Aggressive Saver

Marcus earns well and can save $3,000/month extra. He has a $480,000 loan. Fixed 6.0%, variable 6.4%.

Inputs

loanAmount:480,000loanTerm:25fixedRate:6fixedTerm:3variableRate:6.4splitRatio:40

40/60 split: $192,000 fixed, $288,000 variable. The variable portion allows $36,000/year in extra payments, potentially paying off in 15 years.

§ FAQ

Questions Australians ask

§ Glossary

Plain-English definitions

Split Loan

A mortgage divided into two or more portions with different interest rate types (e.g., fixed and variable).

Split Ratio

The percentage allocation between fixed and variable portions, such as 60/40 or 50/50.

Internal Refinance

Moving money between the fixed and variable portions of your split loan, sometimes possible without break costs.

Loan Facility

The overall loan arrangement that contains the split portions. Each split is technically a separate loan account.

§ Pair it with

Related tools

Compare Fixed vs Variable

Understand the differences before deciding on your split.

Calculate Offset Benefits

See how offset accounts work with your variable portion.

Get Loan Structure Advice

Personalized recommendations on structuring your loan.

How to use

01Enter your total loan amount and term
02Input the fixed and variable rates being offered
03Choose your fixed term length
04Adjust the split ratio to see different scenarios
05Compare total costs and flexibility

Key info

Common splits are 50/50, 60/40, or 70/30 (fixed/variable)
The variable portion can be used for extra repayments
Consider your savings capacity when choosing the split
You can have different offset accounts for each portion

Pro tips

Size your variable portion to handle your likely extra repayments - if you can save $20k/year, keep $100k+ variable
Use offset account on the variable portion to maintain access while still saving interest
Some lenders allow multiple splits - consider a 3-way split with 2 different fixed terms
When the fixed period ends, reassess - you can refix at different amounts if circumstances change

Avoid these

Splitting too much to fixed and losing the flexibility to make meaningful extra repayments
Not considering what happens when the fixed period ends on different dates
Assuming the split is permanent - you can adjust the variable portion anytime
Forgetting that break costs only apply to the fixed portion if you need to exit early

Disclaimer: Estimates only. Interest rates, fees and policies change frequently. Always verify with lenders directly. General information, not personal financial advice.

Last updated · May 2026