How to compare home loans when your business income varies

If you're a business owner in New Zealand, the key is to build your mortgage around the income you can reliably afford to repay, while keeping enough flexibility to handle stronger and weaker months.

You don't necessarily need the lowest advertised interest rate. You need a loan structure that gives you predictable minimum repayments, room to make extra payments when business is doing well, and enough cash available to get through quieter periods.

I'd compare mortgage options across four areas:

• Certainty: Can you comfortably cover the required repayments in a slower month?
• Flexibility: Can you make extra repayments when cash flow is strong?
• Liquidity: Can you keep money accessible for business expenses and unexpected costs?
• Total cost: How much interest and how many fees will you pay for that flexibility?

For many business owners, the best solution is a combination of fixed and floating lending rather than putting the entire mortgage on one type of rate.

1. Compare the four main mortgage structures

These are the options I'd look at first when comparing New Zealand home loans.

Mortgage option	Repayment certainty	Flexibility	Best suited to
Fixed-rate loan	High during the fixed term	Limited extra repayments, depending on lender rules	Covering essential repayments with confidence
Floating-rate loan	Lower, as rates can change	Usually allows extra repayments without fixed-rate break costs	Paying down debt when income is strong
Offset mortgage	Regular repayments, but interest costs can vary	Savings reduce the balance charged interest while remaining accessible	Business owners with cash reserves that fluctuate
Revolving credit mortgage	Lowest repayment structure certainty	High flexibility to deposit and withdraw funds within the credit limit	People with irregular income and strong cash-flow management

These options aren't mutually exclusive. You can often split a mortgage across multiple structures to balance certainty and flexibility. The exact rates, fees and repayment conditions depend on the lender. 【turn0search0】【turn0search4】

Let's look at how each could work for you.

Option A: Fix most of the mortgage

A fixed-rate mortgage gives you a known interest rate for an agreed period, often between six months and five years.

Why it could suit you:

• You know what your scheduled repayments will be during the fixed term.
• You can build your household budget around a predictable amount.
• You have less exposure to interest rate increases during that term.

The trade-off is that you may face restrictions or charges if you want to repay a large amount early, refinance or break the fixed term.

Check how much extra you can repay without a fee. Some lenders allow additional repayments within specified limits. 【turn0search4】【turn0search9】

My view: Fixing a substantial portion of your mortgage is a good starting point if knowing your minimum monthly commitment is your priority.

Option B: Keep part of the mortgage floating

A floating-rate loan lets you make extra repayments more freely than many fixed-rate loans.

For example, suppose your business has a particularly strong quarter and you have $15,000 of surplus personal cash.

You could put some of that money towards the floating portion of your mortgage rather than waiting for the fixed term to end.

If the business has a quieter period, you can retain more cash in the business or your personal reserves instead of committing it to additional mortgage repayments.

The important distinction is that flexibility to make extra repayments doesn't automatically mean you're entitled to reduce or skip your scheduled minimum repayments.

Floating rates can also be higher than fixed rates and can change, affecting the cost of borrowing. 【turn0search0】【turn0search4】

My view: A floating portion can be useful, but I'd size it according to your actual cash-flow needs rather than simply choosing an arbitrary percentage of the loan.

Option C: Consider an offset mortgage

An offset mortgage is particularly worth investigating if you regularly hold money in savings or transaction accounts.

The lender links eligible accounts to your mortgage and calculates interest on the mortgage balance minus the money in those accounts.

For example:

Item	Amount
Total mortgage	$700,000
Eligible savings and cash balances	$50,000
Balance charged interest	$650,000

At an illustrative interest rate of 6%, having $50,000 fully offset for a year would save approximately $3,000 in interest annually, assuming the balances and rate remained unchanged.

You generally retain access to the money in your linked accounts.

This can be attractive for business owners who build up cash reserves in profitable months but need to keep those reserves available.

However, there are two important considerations:

• Offset loans generally have floating interest rates, so the rate can change.
• Money needed for GST, income tax, provisional tax, payroll or business operating costs should not be treated as spare cash available for your mortgage.

Check which accounts qualify and whether the lender's offset arrangements suit your circumstances. 【turn0search0】【turn0search6】

My view: If you maintain substantial cash balances between business receipts and expenses, an offset structure is well worth comparing against simply fixing the same amount.

Option D: Consider revolving credit

A revolving credit mortgage works somewhat like an overdraft secured against your home.

You can deposit income, pay expenses and make withdrawals within the approved limit. The amount of interest you pay depends on the outstanding balance.

This can suit businesses where income arrives irregularly.

However, it requires discipline. Without a separate plan to reduce the principal, you can end up continually using the available credit without making meaningful progress on the mortgage. 【turn0search2】

My view: Consider revolving credit for a limited portion of the borrowing if you are comfortable managing cash flow. I would be cautious about making the entire home loan revolving credit if your primary objective is predictable repayments.

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2. My starting recommendation: combine certainty with flexibility

For your situation, I'd compare a split mortgage against a fully fixed loan and a more flexible arrangement.

Here is an illustrative structure to discuss with a mortgage adviser.

Component	Example allocation	Purpose
Fixed-rate mortgage	75%	Predictable scheduled repayments
Floating or offset mortgage	25%	Flexibility for surplus cash and extra repayments
Total	100%	Balance between certainty and flexibility

These percentages are an example, not a recommendation to borrow those exact proportions. The right split depends on your loan size, cash reserves, income variability and the costs of each product.

You might choose a smaller flexible portion if you have limited spare cash or a larger one if you regularly accumulate substantial savings.

You could also split the fixed portion across different expiry dates. For example, some could mature after one year and the remainder after two years. This spreads out the dates on which you need to renegotiate your rates, rather than having the entire mortgage come up for renewal at once.

Ask lenders whether they offer these arrangements and what fees or conditions apply.

3. Work out the repayment you can actually afford

This is arguably the most important part for business owners.

Your average income may look healthy while concealing months when your personal income is much lower.

Instead of calculating affordability using your best month, use a conservative household cash-flow budget.

I'd work through these four steps.

Step 1: Calculate your reliable personal income.

Review at least 12 months of household income, if available. Identify:

• Your usual personal drawings or salary from the business.
• Your lowest-income periods.
• Seasonal patterns and expected quiet periods.
• Large, irregular distributions or dividends that you cannot rely on every month.

For budgeting purposes, base your planned repayments on a conservative estimate of income available to the household after relevant tax and business commitments.

Step 2: Calculate essential household expenses.

Include groceries, utilities, insurance, transport, childcare, existing debt repayments and annual expenses converted into monthly amounts.

Step 3: Set aside cash for business obligations.

Keep appropriate reserves for tax, GST, payroll, suppliers and working capital. Business revenue in your bank account is not necessarily personal income you can safely use for a mortgage.

Step 4: Establish your safe mortgage payment.

Use the following calculation:

Monthly household income in a conservative scenario
− Essential household expenses
− Business-related personal commitments
− Savings and emergency-fund contributions
= Amount available for mortgage repayments

Then test whether you could continue meeting your mortgage commitments if personal income dropped further or interest rates increased.

For example, if you can comfortably afford a $5,000 monthly repayment in a typical month, but your income regularly falls during quieter periods, you should not assume that $5,000 is automatically a safe commitment.

The crucial question is whether your household can meet the required repayments through those quieter periods without relying on new borrowing.

You can use Sorted's mortgage information and calculators to model different loan structures and repayment scenarios. 【turn0search0】

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4. Compare mortgage offers on more than the interest rate

When you obtain quotes from banks or mortgage advisers, ask them to compare the following on the same borrowing amount and loan term.

What to compare	Why it matters
Interest rate	Determines the interest charged on your outstanding balance
Required repayments	Shows your actual scheduled payment commitment
Fixed-rate expiry dates	Helps you manage the risk of repayments changing
Extra repayment allowances	Determines how much additional principal you can pay without charges
Break costs	Important if you sell, refinance or change your loan early
Offset or revolving rates	Flexible products may have different rates from fixed loans
Account and establishment fees	These affect the overall cost
Redraw and withdrawal conditions	Determines how readily you can access funds
Total interest over time	Helps compare the long-term cost of different structures

Also ask the lender to show you how repayments might change if interest rates were 1–2 percentage points higher when your fixed term expires.

You should compare the offers using the same assumptions, including loan amount, repayment frequency and term. Otherwise, a lower advertised repayment may simply reflect a longer repayment period.

One extra consideration: getting approved as a business owner

A lender may assess your income differently depending on whether you operate as a sole trader, partnership or company.

Be prepared to provide relevant financial statements, tax returns, evidence of drawings or salary, and information about existing business debts.

A profitable business does not necessarily translate into the same amount of income that a lender will recognise for servicing a personal mortgage. Ask prospective lenders how they assess self-employed income and what documentation they require.

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5. The strategy I'd investigate first

Based on what you've described, I'd start by comparing these three scenarios:

1. Mostly fixed: Prioritises predictable repayments and limits the amount of your mortgage exposed to floating rates.
2. Fixed plus offset: Provides repayment certainty while potentially reducing interest through accessible savings.
3. Fixed plus revolving credit: Provides a flexible facility for managing uneven cash flow, provided you maintain strong spending controls.

I'd then compare the actual costs and repayment conditions rather than deciding in advance which structure is best.

If you regularly hold substantial cash reserves, an offset mortgage could be particularly useful. If your cash flow is highly irregular and you actively manage business receipts and expenses, a limited revolving credit facility may be worth considering.

If your cash reserves are relatively small, a predominantly fixed mortgage with a manageable flexible portion may be the more practical starting point.

The goal is to have a mortgage that remains affordable when business is quiet, while allowing you to reduce your debt faster when business is doing well.

Let’s narrow this down to your situation

There are two details that would help me make the comparison much more specific.

1. How do you and your business partner (if applicable) pay yourselves?

• Regular salaries or wages
• Drawings from a sole-trader business or partnership
• Dividends or distributions from a company
• A mixture of these

2. How does your income typically fluctuate?

• Fairly steady, with occasional large months
• Seasonal, with predictable busy and quiet periods
• Highly variable, with no reliable monthly pattern

You can answer in a sentence. With those details, I can explain which mortgage structures are most worth comparing for your circumstances and what trade-offs to look for.