Debt-to-income (DTI) is one of the key factors lenders use to assess how much you can borrow. If your DTI is too high, it can limit your chances of mortgage approval even if you have a strong income or a healthy deposit sitting ready to go.
If you’d like a detailed breakdown of what DTI is and how it’s applied here in New Zealand, take a look at our article on debt-to-income ratios in New Zealand.
Your debt-to-income ratio compares your total debt to your gross income. Lenders use it as a guide to gauge whether you can comfortably manage mortgage repayments on top of your existing financial commitments.
It might look like a straightforward calculation on paper, but in practice, DTI carries real weight and it shapes your borrowing power and can either narrow or expand he options available to you.
If your DTI sits above what a lender is comfortable with, you may find that you:
In practice, lender can vary quite a bit in how they assess this, which is why outcomes aren’t always as straightforward as they first appear.
We know that can feel deflating, especially when your income feels more than sufficient to support the loan you’re after.
The good news is that a high DTI isn’t always a dead end. There are often practical steps you can take to strengthen your position before you apply.
Paying down credit cards, personal loans, or car finance can make a direct and meaningful difference to your DTI, as well as to how lenders assess your overall application.
How your loan is structured can affect affordability calculations more than people realise. For example:
If you want to understand how different lending structures work, our article on investment property mortgage options in New Zealand is a good place to start.
Not all lenders treat income the same way. This matters particularly if your income includes:
Knowing how a lender is likely to assess your income can help you present your application in the best possible light.
If the main banks are restrictive because of DTI limits, some non-bank lenders may offer more flexibility depending on your broader financial picture.
This isn’t about taking on unnecessary risk, it’s about knowing what options exist and whether they make sense for your situation. If you’re thinking about using existing assets to fund an investment property, it’s worth reading about using equity to buy and investment property in New Zealand and how that works in practice.
For property investors, DTI becomes an increasingly important factor as your portfolio grows. Even with solid equity or a strong deposit in place, your ability to keep borrowing can be constrained by the total debt you’re carrying relative to your income.
We often see investors get caught off guard by this as they scale up — planning ahead and understanding how DTI affects your position can make a real difference to how strategically you’re able to grow.
If you’re not sure how your DTI is affecting your borrowing power, or what steps you can take to improve your position, it can help to speak to someone who understands how lenders assess applications in practice. We can review your situation and help you understand what options are available – contact us. At Platinum Mortgages, we look at your full financial picture, not just a single ratio and work with you to structure your lending in a way that supports your long-term goals.
Angela is an accredited Financial Adviser, licensed under FSP742251 and has been in the Financial Industry since 2006. Our 5-star Google reviews reflect the excellent customer experience we promise — making your home loan journey positive, stress-free, and rewarding. At Platinum Mortgages, our clients are the reason we exist — so you can be confident every step is guided by genuine care and expertise.
