Question 1

What is a split mortgage structure?

Accepted Answer

A split mortgage divides one loan into two or more components (sometimes called suffixes or facilities) that can carry different rates, terms, and repayment behaviours — for example a fixed portion, a floating portion, and an offset-linked portion. Splitting lets borrowers balance certainty, flexibility, and interest cost in one overall loan.

Question 2

When does splitting a mortgage actually save money?

Accepted Answer

Splitting helps when different parts of the loan benefit from different strategies at the same time — for instance, fixing a portion to lock in a known rate while keeping another portion floating in case rates fall. It also helps direct overpayments and offset balances to the highest-cost portion first.

Question 3

How many components can a split mortgage have?

Accepted Answer

Most NZ lenders support two to four components on a single loan, though some allow more. This tool lets you model up to five components per scenario so advisers can compare more aggressive structures side by side.

Question 4

How does the offset account integrate with a split mortgage?

Accepted Answer

An offset account reduces the effective principal used to calculate interest. With a split mortgage, the offset is typically shared across all components. This tool defaults to allocating the offset proportionally to each component’s principal, with an advanced override if you want to direct it manually.

Question 5

What does the unified amortisation schedule show?

Accepted Answer

It rolls up all components into a single month-by-month view of the total balance owed, total interest paid, and total principal paid. This is useful for understanding how quickly the overall loan will be paid off under each strategy.

Question 6

Can I share my scenario with a Mortgage Lab adviser?

Accepted Answer

Yes. Every state change updates the page URL with a compact, shareable code. Send the URL to your adviser and the entire scenario — components, rates, overpayments, offset — will load on their end exactly as you left it.

Question 7

Does this tool show break fees or refinance costs?

Accepted Answer

No. Splitting, fixing, or breaking a component mid-term can trigger break fees that vary by lender. Use this tool for structure and timing decisions, and confirm the lender-specific costs with a Mortgage Lab adviser before changing your loan.

Question 8

Are overpayments limited?

Accepted Answer

Many lenders cap annual overpayments at around 5% of the original principal on fixed components. Floating components are usually more flexible. The tool surfaces this as an information note and does not enforce a cap — check your loan terms before relying on overpayments to shorten the term.

Advanced Mortgage Structure Tool

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