Flatmate & Boarder Income: A Straightforward Guide to Mortgage Lending Rules in NZ
A quick heads-up before we dive in: This article is for general information only and isn't personalized financial advice. Everyone's situation is unique. Before making any decisions about your property journey or mortgage structure, it's always best to chat directly with a qualified financial adviser.
When you are looking to boost your borrowing power for a home loan, planning to get a flatmate is a common and practical strategy. While you likely refer to them as flatmates, banks formally classify this as "boarder income" on a mortgage application.
Because this extra cash flow can directly increase the amount a bank is willing to lend you, lenders look closely at how you declare this income to ensure your application is completely realistic.
Here is a straightforward look at how the maths works for flatmate income, the room requirements you need to meet, and how this strategy can actually give you a massive financial head start on your home loan.
How Flatmate Income Affects Your Borrowing Capacity
Lenders do not simply take the amount of rent you plan to charge and add it directly to your application. Because flatmates can move out or rooms can sit vacant, banks apply a conservative buffer to the numbers to protect your budget.
Standard Allowances: Most New Zealand banks will credit a flatmate's contribution at a fixed baseline—typically between $150 and $250 per week, per person, depending on the specific lender's policy.
The Deposit Hurdle: If you have a standard 20% deposit (or higher), banks are generally happy to count income from up to two flatmates. However, if you are applying for a low-deposit home loan (with less than a 20% deposit), some banks will only allow you to claim for one flatmate, or they may exclude flatmate income entirely.
The Room Requirement: The Maths Must Match the Property
A core rule of a home loan application is that your living arrangements must match the physical reality of the house you are buying.
To claim income from a flatmate, the property must have a physical, vacant bedroom available to accommodate them. For example, if you are a couple, the bank assumes you will share the main bedroom. That means to claim for two flatmates, you would need a three-bedroom home minimum.
Test out your own household setup using our quick calculator below to see exactly how many bedrooms you'll need:
How many bedrooms do I need?
Find out exactly how many bedrooms a bank will require your new home to have if you plan on using flatmate income to support your application.
The Golden Rule: The bank will only accept flatmate income if your application clearly matches the number of spare bedrooms in the specific home you plan to buy.
The Real Positives of Having Flatmates
Beyond just getting your mortgage approved, having a flatmate in the early days of your homeownership journey can be a massive financial advantage.
When you first buy a house, a large portion of your early mortgage repayments goes strictly toward interest. By using that extra $150 to $250 a week from a flatmate to make additional principal payments on your loan, you can shave years off your mortgage and save tens of thousands of dollars in interest over the long run. It is one of the smartest ways to aggressively pay down your debt while your budget is still adjusting to the reality of owning a home.
When Can You Stop Having Flatmates?
A common question buyers ask is: "Am I locked into having flatmates for the entire life of the mortgage?"
The short answer is no, but your intention at the time of buying really matters. When you apply for your loan, having a flatmate must be your genuine, real-world plan for how you intend to live in the property. The bank is approving the loan based on that reality, and they do sometimes follow up after settlement to make sure that rental income is actually hitting your bank account.
However, life changes. Once the loan settles and you are living in the home, you aren't legally obligated to keep flatmates forever. From a practical budgeting perspective, many people naturally transition to living alone (or reclaiming those spare bedrooms) once their personal income increases enough to easily cover the mortgage on its own, or when they have paid down the loan balance enough that the monthly payments become much more comfortable.
The Bottom Line
Using flatmate income is a completely legitimate, standard pathway to homeownership, provided the maths is grounded in reality and reflects your genuine living plans. It is a tool designed to get you across the starting line, backed by rules that ensure you aren't taking on more than you can realistically handle.
Want to see how a flatmate's contribution could realistically change your borrowing options? Get in touch with the team at Home Loan Factory today for a clear, transparent second opinion on your numbers.
