Mortgage Calculator

Understanding your borrowing capacity is the first step to buying your first home or your dream home. Use the tool below to understand roughly what your borrowing capacity is.

Borrowing Capacity

1Property type

Loan purpose

Owner-occupier RBNZ debt-to-income cap: 6× gross income.

Loan term (years)

2Deposit

Deposit available ($)

Target property value ($)

3Your situation

Number of applicants

Applicant 1 — gross annual salary/wages ($)

Other regular income, after tax ($/yr) — bonus, self‑employed profit, overtime

Rental income — gross ($/week, all properties)

Rental income is assessed at 75% of gross to allow for costs and vacancy — the standard rate banks apply.

4Household & expenses

Your monthly living expenses ($/month, optional — leave blank to use the standard bank benchmark)

Dependent children (under 18)

Banks use whichever is higher: what you declare, or a standardised minimum living-cost benchmark for a household like yours. This calculator does the same.

5Other debts

Total credit card / overdraft limits ($)

Other loan/HP/other mortgage repayments ($/month)

Total balance owing on other loans/mortgages ($)

Credit cards are assessed at 4% of the limit per month, whether or not it's used — the standard bank approach.

Estimated borrowing capacity

Enter your details to see an estimate

Potential purchase price

Deposit available$0

Plus: estimated lending$0

Potential purchase price$0

Resulting LVR0%

Indicative monthly repayment

At % p.a. on this loan amount

How this is calculated

1. Net income: salary/wages are taxed using current NZ PAYE brackets plus the ACC earner levy, to estimate take-home pay. Other regular income and rental income (haircut to 75% of gross) are added on top.

2. Living expenses: the higher of what you declare or a standardised minimum benchmark: a base amount for the household, plus an amount for a second applicant, plus an amount per dependent child — the same structure banks use to floor declared expenses that look unrealistically low.

3. Existing debts: credit cards are loaded at 4% of the limit per month regardless of balance, plus any other loan, hire purchase or mortgage repayments you enter.

4. Serviceability test: your leftover income (UMI) is used to work out the largest loan repayable at the bank's stress-tested interest rate over your chosen term — not the advertised rate, a higher rate that builds in a buffer for future rises.

5. Debt-to-income (DTI) cap: RBNZ rules cap total debt (new loan + existing debt) at 6× gross income for owner-occupiers and 7× for investors. New builds are currently exempt. Your final estimate is the lower of the servicing-based and DTI-based figures.

This tool gives a general, indicative estimate only. Its calculations are calibrated against the real servicing mechanics used by a major New Zealand bank (income tax treatment, living cost benchmarks, debt loading and stress-test methodology), simplified into a fast, lender-agnostic ballpark figure. It is not affiliated with, endorsed by, or a copy of any specific lender's tool, and every bank applies its own policies, buffers and discretion. Actual borrowing capacity can only be confirmed by a registered bank or mortgage adviser through a full application.