How much could your household budget support? This NZ mortgage affordability calculator estimates a loan amount from your take-home income and monthly costs, using a fixed illustrative 8% interest rate. It is a starting point for a conversation with Eddie, not bank approval or a lender's borrowing limit.
Your figures stay in this calculator in your browser. They are not saved or sent to Eddie. The contact link does not include them.
How the calculator works
Start with the income your household actually receives. We subtract the monthly living costs, existing debt repayments, future ownership costs and safety allowance you enter. The amount left is your illustrative monthly mortgage repayment budget.
For example, $6,000 take-home income less $2,400 living costs, $350 debt repayments, $450 ownership costs and a $300 safety allowance leaves $2,500 a month. At the fixed illustrative 8% rate over 30 years, that supports a budget estimate of approximately $340,000, rounded down.
The model divides 8% by 12 and uses monthly principal-and-interest amortisation over your selected term. It assumes the same rate throughout, with no fees or repayment changes. Weekly income is multiplied by 52 / 12; fortnightly income by 26 / 12. Estimates are rounded down in $5,000 bands, but target-loan comparisons use the unrounded figures.
What banks also look at
A lender will assess more than the amount left in this budget. Dependants, lender expense benchmarks, credit history, card limits, income stability and existing commitments can all affect its assessment. A lender may use different income and expense figures, and its own repayment assessment rate.
Debt-to-income (DTI) considers debt relative to gross income; loan-to-value (LVR) considers lending relative to property value. This calculator applies neither set of lending limits. The deposit source, property, valuation, insurance and lender requirements still need checking. A comfortable budget alone does not establish eligibility.
What if I am a first-home buyer?
Use this to begin planning, before choosing a price range to rely on. Keep money aside for purchase costs as well as ongoing rates, insurance and maintenance. Your optional deposit should be what remains available for the purchase after those upfront costs.
If KiwiSaver or family help forms part of your deposit, the amount and conditions need confirming separately. Before committing to a home, talk through finance conditions with Eddie and get legal advice on the agreement.
What if my finances are more complicated?
Self-employment, irregular earnings, rental income, multiple properties or a planned change in work need a closer look. This tool cannot decide which income a lender will accept, model investment tax or assess a business. Eddie can help you work through the documents and circumstances behind the numbers.
Questions about your estimate
Is this a bank approval?
No. It is an illustration using your stated budget. It does not check your credit file, verify income or assess a property. A lender must assess an application before offering finance.
Why 8%?
Best Mortgages has chosen a fixed illustrative 8% rate so comparisons use one clear assumption. It is not a bank quote, historical average or prediction. Your actual rate and a lender's assessment rate may differ.
Does my deposit matter?
Yes, but it does not increase the repayment budget calculated here. The optional property illustration adds your available deposit to the unrounded loan estimate, then rounds down. It does not confirm that the deposit or property meets a lender's requirements.
What expenses should I enter?
Use realistic ongoing household spending, debt payments, home ownership costs and a safety margin. Avoid counting a payroll deduction twice. Only leave out current rent if it will cease when you buy; allow for any overlap separately.
How can Eddie assess my borrowing?
Eddie can review your income, spending, debts, deposit and plans, then check suitable lender requirements. Use the contact link to arrange a conversation. Your calculator figures are not passed through automatically.
Put your budget in context with Eddie
I'm Eddie Biesenbach, based in Tauranga and helping clients across New Zealand through online meetings. I start with your finances before approaching a lender, looking at income, spending, debts and account conduct alongside your deposit. If preparation is the useful next step, I can help you work out what to focus on.
A number on a screen is a starting point. I can help you understand how your budget, plans and the property fit together before you rely on a borrowing figure.
Talk with Eddie about your next stepAssumptions, limitations and privacy
This educational estimate uses only what you enter. It does not apply bank policies, tax calculations, DTI or LVR thresholds, eligibility rules or current interest rates. It excludes lender fees and assumes regular monthly repayments with no change in rate, income or expenses. Actual repayment calculations and lender decisions may differ.
The calculator runs locally in your browser. It does not submit, retain or transmit your income, costs, deposit or target loan, and does not put them in a link or contact form. Clear figures or reload to start again. The normal site privacy and disclosure links remain in the footer.
For input checking, budget entries are limited to $1,000,000 per entered period and optional deposit or target-loan entries to $100,000,000. These are technical safeguards, not lending limits. For unusual circumstances, speak with Eddie.
