What is Borrowing Capacity and How is It Calculated?

Your borrowing capacity is the maximum amount a lender will let you borrow based on your income, expenses, and financial commitments.

Lenders assess your capacity by looking at your household income, your existing debts, your living expenses, and the interest rate buffer they're required to apply under lending regulations. The buffer means you're assessed at a rate roughly 3 percentage points above the actual loan rate, which reduces the amount you can borrow but also protects you from payment stress if rates rise.

How Lenders Calculate What You Can Borrow

Borrowing capacity is calculated using your net income after tax, minus your committed expenses and liabilities, with a serviceability buffer applied to the loan repayment.

Consider a couple earning a combined income of $160,000 before tax who have a car loan with $400 monthly repayments and typical living expenses for two people. The lender will calculate their net monthly income, deduct the car loan repayment, apply a benchmark living expense figure based on the Household Expenditure Measure, and then assess whether they can afford the loan repayments at a rate 3 percentage points above the variable rate they're applying for. The buffer is set by the Australian Prudential Regulation Authority and applies across all banks and lenders. If the couple's after-tax income is around $10,500 per month, their car loan costs $400, and their assessed living expenses come to around $3,200, they're left with roughly $6,900 in surplus income. The lender then tests whether that surplus can service the monthly repayment on their desired loan amount, calculated at the buffered rate. This calculation determines the maximum loan amount they can access.

The Role of Debt-to-Income Limits in Nedlands

From February 2026, lenders can only approve a limited portion of new loans to borrowers with a debt-to-income ratio of six times or more.

A borrower in Nedlands earning $120,000 who wants to borrow $750,000 would have a debt-to-income ratio of 6.25. That loan can still be approved, but it now falls within the 20 per cent cap that applies to the lender's total lending in that quarter. This doesn't mean the loan is automatically declined, but it does mean lenders are managing their approvals more carefully at higher multiples. Properties in Nedlands typically sit above the Perth median, so buyers in this area are more likely to encounter debt-to-income considerations during assessment. If your borrowing need pushes you above six times your income, your application may take longer to assess or require a larger deposit to bring the ratio down.

What Reduces Your Borrowing Capacity

Existing debts, credit card limits, and understated living expenses will all reduce how much you can borrow.

Credit card limits are assessed based on the limit itself, not the balance you're carrying. If you have a card with a $15,000 limit and you're only using $2,000 of it, the lender will assume you could draw down the full $15,000 and will factor in a monthly repayment of around 3 per cent of the limit when calculating your capacity. That's roughly $450 per month being deducted from your surplus income, even if you never use the card. Closing accounts or reducing limits before you apply can improve your borrowing power. Buy now, pay later accounts are also included in serviceability assessments. Personal loans, car finance, and HECS or HELP debts all reduce capacity as well. HECS repayments are calculated as a percentage of your income and deducted before the lender assesses your net position.

Living expenses are another key factor. Lenders use the greater of your declared expenses or a benchmark figure based on the Household Expenditure Measure, which varies depending on household size and income level. If you're a single person earning $90,000, the lender may apply a monthly living expense figure of around $2,000 to $2,500 even if you declare lower costs. Families with dependents will have higher benchmarks applied.

Loan Structure and Borrowing Power

Your choice between variable, fixed, or interest-only loans can affect how much you're approved to borrow.

Variable rate loans are generally assessed at the advertised variable rate plus the 3 percentage point buffer. Fixed rate loans are assessed at the fixed rate plus the buffer if the fixed period is longer than three years, or at the variable rate plus buffer if the fixed period is shorter. Split rate loans are assessed using a blended rate. Interest-only loans reduce your monthly repayment during the interest-only period, but lenders assess your capacity based on principal and interest repayments over the full loan term, so choosing interest-only won't increase how much you can borrow unless the lender applies a different serviceability policy for investors.

For owner-occupiers buying in Nedlands, where property values are above average, loan structure becomes relevant when you're trying to maximise your borrowing power without overcommitting. A split loan gives you certainty on part of your debt while keeping flexibility on the rest, but it doesn't increase your assessed capacity.

Improving Your Borrowing Capacity Before You Apply

Paying down existing debt, increasing your deposit, and reviewing your expenses will all improve how much you can borrow.

If your borrowing capacity falls short of what you need, the most direct way to improve it is to reduce your liabilities before applying. Paying off a car loan or personal loan removes that monthly commitment from your assessment. Cancelling unused credit cards or reducing limits has an immediate effect. Increasing your deposit doesn't change your income or expenses, but it does reduce the loan amount you need, which can bring your debt-to-income ratio below six times and make your application more likely to be approved.

You can also improve capacity by applying with a co-borrower, provided their income exceeds their liabilities. If you're purchasing with a partner or family member, their income will be added to the household figure and assessed alongside their commitments. In some cases, a guarantor can help you borrow more by using equity in their own property to support your application, though this involves risk for the guarantor and requires independent legal advice.

Another option is to speak with a mortgage broker who can assess your position across multiple lenders. Different lenders apply different living expense benchmarks and have different appetites for higher debt-to-income loans. One lender may assess your capacity at $650,000 while another offers $690,000 based on the same income and commitments. A broker can identify which lender is likely to give you the highest approval and structure your application accordingly.

Understanding Pre-Approval and Capacity

Home loan pre-approval gives you a formal indication of your borrowing capacity before you start looking at properties.

Pre-approval is based on the same assessment as a full approval but without a specific property attached. The lender reviews your income, expenses, debts, and credit history and confirms how much they're willing to lend. Pre-approval is usually valid for three to six months and gives you confidence when making an offer, particularly in a suburb like Nedlands where competition for established homes can move quickly. If your circumstances change during the pre-approval period, such as taking on new debt or changing employment, your capacity may be reassessed when you proceed to full approval.

If you're looking to understand your borrowing capacity or want to explore ways to improve it before applying, call one of our team or book an appointment at a time that works for you.

Frequently Asked Questions