The Finance AlgorithmTFA

Split Loan Calculator

Calculator

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

Free to useNo data storedAI insightsUpdated: February 2026

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.

Enter Your Details

Enter Your Details

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What percentage should be fixed? (remaining will be variable)

Real-World Examples

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.

Frequently Asked Questions

Glossary

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.

Disclaimer: This calculator provides estimates only and should not be relied upon for financial decisions. Interest rates, fees, and policies change frequently. Always verify information with lenders directly. This is general information, not personal financial advice. Consider seeking advice from a licensed mortgage broker or financial advisor.

Last updated: February 2026

How to Use
  1. Enter your total loan amount and term
  2. Input the fixed and variable rates being offered
  3. Choose your fixed term length
  4. Adjust the split ratio to see different scenarios
  5. Compare total costs and flexibility
Key Information
  • 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 Mistakes
  • 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
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