What Car Loans and Credit Cards Really Cost You

The rule that surprises everyone

For revolving credit — credit cards and overdrafts — most New Zealand lenders assess a notional monthly repayment calculated against your credit limit, not your current balance. The logic is that you could max the card tomorrow, so the lender must assume you might.

That produces a counterintuitive result. A credit card with a $15,000 limit and a zero balance still reduces your borrowing capacity, often substantially. You are being assessed as though you owe the full limit and are repaying it.

How each debt type is treated

The pattern: for revolving facilities the limit is what matters, and for term debt the contracted repayment is what matters.

Why a car loan hits harder than its size suggests

Car loans are usually assessed on the actual repayment, which sounds fair. The problem is the scale of the repayment relative to the balance — consumer car finance is typically repaid over a short term, so the monthly commitment is large for the amount owed.

A car loan with a modest remaining balance but a substantial monthly repayment consumes serviceability out of proportion to the debt. And every dollar of monthly commitment removed translates into a multiple of that in additional mortgage capacity, because a mortgage is assessed over a much longer term.

This is why the question is rarely 'should I pay off debt or save deposit' in the abstract. It depends which debt. Clearing a car loan with high repayments relative to its balance often does more for your borrowing power than the equivalent added to your deposit. Clearing a student loan generally does not.

The order to deal with things

1. Cancel or reduce unused credit card and overdraft limits. Free, immediate, and often the biggest single gain.
2. Clear small consumer debts — store cards, hire purchase, interest-free arrangements. Individually minor, collectively meaningful, and they clutter your statements.
3. Close BNPL facilities three to four months before applying. See our guide to BNPL on applications.
4. Then assess the car loan. If it can be cleared without gutting your deposit, usually worth doing. If clearing it would push you into a worse loan-to-value band, model both scenarios first.
5. Leave the student loan unless the balance is small enough to clear outright. See why paying it down may not help.

Debt consolidation: useful or counterproductive?

Consolidating several debts into one loan can simplify your position and reduce total repayments, which helps serviceability. But timing matters. Taking out a new personal loan weeks before a mortgage application creates a fresh credit enquiry, a newly documented term debt, and a statement history showing recent borrowing — none of which helps.

Where consolidation genuinely helps is when it is done well in advance and demonstrably reduces your total monthly commitments. If your debt position is complex, it is worth modelling with a broker before restructuring anything. Our debt consolidation case study shows how one client approached it.

Model it before you act

The frustrating part of all this is that the arithmetic differs by lender. Notional credit card repayment rates vary, as do treatment of interest-free arrangements and how surplus is calculated. The same set of debts can produce materially different maximum lending at different banks.

That is worth using rather than worrying about. Send us a list of your debts, limits and repayments. We will model your capacity across lenders and tell you specifically which actions buy you the most — so you are not paying down the wrong thing for six months.

Why removing a repayment buys so much mortgage capacity

The reason clearing short-term debt has an outsized effect is the difference in term. A car loan might be repaid over five years; a mortgage is assessed over thirty. So a dollar of monthly commitment removed from the short-term debt frees up a dollar of monthly capacity that can support a much larger amount of long-term borrowing.

The precise multiple depends on the lender's stress-test rate and assessment term, and it is not something to calculate on the back of an envelope — but the direction is reliable and the magnitude is usually surprising. This is why we ask clients for a full list of commitments before talking about property prices.

Credit limits: the free win most buyers miss

Because revolving facilities are assessed against the limit rather than the balance, reducing limits costs you nothing and can move your capacity materially. What to do:

1. List every credit card, store card and overdraft with its limit — including ones you never use.
2. Decide the minimum limit you genuinely need for emergencies. Many buyers find the honest answer is zero or a small buffer.
3. Ask your bank to reduce the limits in writing, or close the facilities entirely.
4. Get written confirmation of the closure or reduction, because your broker will need to evidence it.
5. Do this before the application, not during it. A limit reduction processed mid-assessment creates confusion.

One caution: closing your oldest credit account can slightly affect your credit file, since length of credit history is one factor in a score. In practice the serviceability gain from removing a large limit almost always outweighs that, but if you have several cards, keep the oldest with a small limit and close the rest.

Interest-free and buy-now-pay-later finance still counts

Store finance arranged as twelve or twenty-four months interest-free feels free, and in interest terms it is. But it is a contracted term debt with a monthly repayment, it appears on your credit file in most cases, and lenders assess the repayment like any other.

The same applies to:

• Furniture and appliance finance on deferred-payment terms.
• Mobile phone plans with a handset repayment component.
• Gym and service contracts with a fixed term you cannot exit.
• Vehicle leases and novated arrangements, which are sometimes overlooked because they are not called loans.

Declare all of it. These arrangements show on bank statements and often on credit files, and an undeclared commitment that the assessor finds is worse than a declared one — it calls the rest of your application into question. Our document checklist covers what to gather.

This article explains how New Zealand lenders generally assess these situations. It is general information, not personalised financial advice, and lender policy changes often — check your own position with a registered adviser. Official sources: Reserve Bank of New Zealand for lending policy and the OCR, and Sorted.org.nz for independent government-backed money guidance.