Use this calculator to estimate your maximum mortgage borrowing capacity in New Zealand. Results are based on the RBNZ’s DTI 6× cap and a stress-tested serviceability assessment — the two tests all NZ banks apply.

Quick answer

NZ's DTI 6× rule means your maximum mortgage is roughly 6 times your gross annual income, minus any existing debts. On $100,000 income with no other debt, that's $600,000. Add a $150,000 deposit and you could purchase up to $750,000 — subject to a bank serviceability stress test at approximately 7.5%–8.5%.

Borrowing Calculator

Your gross annual income ($)

Co-borrower gross annual income ($ — leave 0 if solo)

Existing debt total (car loan, personal loan, student loan balance $)

Total credit card limits ($)

Your deposit ($)

How the Calculator Works

This calculator applies the RBNZ’s DTI 6× rule — the primary constraint on NZ mortgage lending since July 2024.

Step 1: Total debt capacity Total allowable debt = Gross household income × 6

Step 2: Subtract existing debt Existing loans (car, personal, student loan balances) and credit card limits are counted toward the DTI. These reduce how much mortgage is available.

Step 3: Maximum mortgage Maximum mortgage = Total debt capacity − existing debt − credit card limits

Step 4: Property price Maximum property price = Maximum mortgage + your deposit

What’s Not Captured in This Calculator

This calculator gives a DTI-based estimate. Your actual borrowing capacity also depends on:

Serviceability stress test Banks test whether your income can service the mortgage at rates ~2%–3% above current market (approximately 7.5%–8.5%). For some borrowers — particularly those with high expenses or dependants — the serviceability test will produce a lower result than DTI.

Living expenses and dependants Banks assess your actual living expenses (or their benchmark, whichever is higher) and reduce available income accordingly. Each child reduces assessed surplus by approximately $10,000–$15,000/year.

Lending policy differences Different banks apply DTI and serviceability rules slightly differently. A mortgage broker can compare your application across multiple lenders.

See How Much Can I Borrow? for the full picture.

Borrowing by Salary — Detailed Pages

Frequently Asked Questions

What is the maximum NZ mortgage I can get on a $100,000 salary?

Under the DTI 6× rule, the theoretical maximum mortgage on $100,000 gross income with no existing debt is $600,000. Add a $150,000 deposit and you could potentially purchase a $750,000 property. The bank’s serviceability stress test at ~7.5%–8.5% may produce a lower offer.

How does the borrowing calculator work for a couple in NZ?

For joint applications, combined gross income is multiplied by 6, then existing debt is subtracted. Two borrowers earning $70,000 and $65,000 ($135,000 combined) have a DTI cap of $810,000. Both borrowers’ debts, credit card limits, and living expenses are combined in the full assessment.

What reduces my borrowing capacity most in NZ?

The biggest reducers are: credit card limits (each $10,000 of limit reduces mortgage capacity by ~$30,000–$40,000), personal and car loans (full balance counts), student loans (reduce both income and debt capacity), and dependants (~$10,000–$15,000 per child in bank expense benchmarks).

Does the borrowing calculator include the bank’s serviceability test?

No — this calculator estimates borrowing capacity based on DTI 6× only. Banks also apply a serviceability stress test at approximately 7.5%–8.5%, assessing whether your income covers repayments at that rate after all living expenses. For some borrowers — particularly those with high expenses — the serviceability test produces a lower limit than DTI.

How accurate is the NZ mortgage borrowing calculator?

This calculator gives a reliable DTI-based estimate for most standard borrowers. It will be less accurate for self-employed borrowers (income averaging rules differ), those with commission or variable income (banks shade these), and complex financial positions. For an accurate figure, get a bank pre-approval or speak with a mortgage broker.

NZ Mortgage Borrowing Calculator — How Much Can I Borrow? (2026)