Beginner's Guide to Serviceability Assessment

A serviceability assessment determines how much a lender will let you borrow based on your income, expenses, and existing debts.

Every lender uses a different calculation. They assess whether you can afford the repayments not just at today's rate, but at a higher buffer rate that accounts for future rate rises. They also add in minimum living expenses that often exceed what you actually spend, which is why the amount you can borrow is almost always lower than what you think you can afford. If you earn $100,000 and have no debts, one lender might approve $650,000 while another approves $720,000. The assessment is not about what you think you can manage. It is about what the lender's calculator says you can prove.

What Gets Counted as Income

Lenders accept your base salary at 100%, but everything else is discounted or excluded. Bonuses and commissions are usually counted at 80% if you have received them consistently for two years. Overtime is treated the same way. Rental income from an investment property is shaded by 20% to account for vacancy periods and maintenance, meaning a property generating $500 per week only adds $400 to your borrowing capacity. If you are self-employed, lenders average your last two years of taxable income, which means any deductions you claimed to reduce your tax bill also reduce how much you can borrow. Centrelink payments, including Family Tax Benefit and parental leave, are generally excluded.

Consider a buyer on the Gold Coast earning $95,000 in base salary plus $15,000 in annual bonuses. If the bonus history is patchy or only started this financial year, the lender might exclude it entirely. That drops the assessed income to $95,000, which can reduce borrowing capacity by $80,000 or more depending on other commitments. If the bonus has been paid consistently, it gets shaded to $12,000, lifting capacity but not by the full amount.

How Lenders Calculate Your Expenses

Your actual spending does not matter as much as you think. Lenders use a minimum living expense benchmark called the Household Expenditure Measure (HEM), which is based on Australian Bureau of Statistics data and scaled to your household size and income. If you are single and earn $90,000, the lender might apply a monthly expense figure of $2,200 even if you only spend $1,600. If you have two dependents, that figure jumps to $3,500 or more. You cannot argue it down by showing your bank statements unless your actual declared expenses are higher, in which case the lender uses the higher figure.

Credit card limits are treated as if they are fully drawn, even if you pay the balance in full each month. A card with a $10,000 limit costs you roughly $50,000 in borrowing capacity because the lender assumes you could max it out tomorrow. This is one of the most common serviceability killers for Gold Coast buyers who carry multiple cards or store credit accounts. Buy now, pay later accounts such as Afterpay are also included. Each active account with a limit is assessed as a liability.

The Assessment Rate and Buffer

Lenders do not assess your repayments at the actual interest rate you will pay. They test your serviceability at a higher assessment rate, typically the loan rate plus a buffer of 3%. If you are applying for a variable loan at 6.2%, the lender assesses whether you can afford repayments at 9.2%. This buffer is set by the Australian Prudential Regulation Authority and applies across all lenders, though some add an extra margin on top depending on your profile. The assessment rate is why a borrower who can comfortably afford the actual repayment still gets knocked back or approved for less than expected.

Fixed rate loans are assessed at the fixed rate plus the buffer for the fixed period, then at a higher revert rate plus buffer for the remaining term. If you are fixing at 5.8% for three years, the lender will test the first three years at roughly 8.8%, then the remaining 27 years at a variable rate of around 6.5% plus 3%. This makes fixed rate applications slightly harder to service in the short term, though the difference is marginal.

Investment Property and Existing Debt

If you already own an investment property, the lender will assess the full loan repayment against your income, then add back 80% of the rental income as discussed earlier. The net result is usually a drag on capacity unless the property is generating strong positive cash flow. Interest-only loans on investment properties can help with cash flow, but they do not improve serviceability in the assessment because lenders test them as if you are paying principal and interest.

Existing home loans, personal loans, and car finance all reduce what you can borrow. A $30,000 car loan with $700 monthly repayments will cut your borrowing capacity by around $140,000. If you are refinancing or looking to increase your borrowing capacity, paying out short-term debts before applying can make a material difference. The same applies to HECS or HELP debt, which is calculated as a percentage of your income and deducted before the lender runs the assessment.

Why Your Scenario Might Not Fit the Standard Model

Some income types require manual assessment or fall outside the automated decisioning systems that most lenders use. If you are a shift worker with penalty rates, a contractor with ABN income, or receiving a retention bonus tied to a future vesting date, the standard calculator might understate your capacity or reject the application outright. This is where a broker can submit to a lender with more flexible income policies rather than letting the algorithm make the call. For example, some lenders accept 100% of overtime for emergency services workers or FIFO employees, while others stick to 80% regardless of occupation.

If you are purchasing in a regional centre such as the Gold Coast or Tweed Heads, some lenders apply postcode-based adjustments that reduce your borrowing capacity slightly compared to metro areas. This is not disclosed upfront and only shows up when the application is lodged. It is not universal, but it exists.

What You Can Do Before Applying

Close or reduce credit card limits you are not using. Even a card you opened years ago and forgot about will show up on your credit file and cost you capacity. If you have a $20,000 limit across two cards and you only ever use $3,000, call the bank and drop the limits to $5,000 total. You will add $75,000 or more to your borrowing amount. Pay off small debts in full rather than leaving them on a payment plan. A $4,000 personal loan with eight months remaining is holding back $40,000 in capacity for the sake of a debt you could clear tomorrow.

If you are self-employed, talk to your accountant before lodging your next tax return. Every dollar you claim as a deduction reduces your taxable income, and lenders use taxable income to assess your application. If you are planning to buy in the next 12 months, it might make sense to pay more tax this year and claim fewer deductions so your income on paper supports the loan you need. You can discuss your home loan application options with a broker before you reach that point so you know what income figure you are working toward.

Do not change jobs in the months leading up to an application if you can avoid it. Most lenders require three months of payslips, and some want six if you are still on probation. If you are moving from permanent employment to a contract or casual role, expect lenders to apply a loading or require 12 months of history in the new role before they will assess the income.

When It Makes Sense to Apply to Multiple Lenders

A pre-approval from one lender does not tell you what you could borrow elsewhere. Lenders have different expense benchmarks, different ways of treating investment income, and different appetites for certain occupations or income structures. If you are a first home buyer on the Gold Coast working through the Australian Government 5% Deposit Scheme, some participating lenders will assess your capacity more favourably than others, even though the guarantee structure is identical. If you are knocked back or the amount approved is lower than expected, a broker can try a different lender with a better fit for your profile rather than assuming the first answer is final.

Serviceability is one part of the lending decision. Credit history, deposit size, and property type also matter. But it is the part that catches buyers off guard because the calculation is invisible until the application is submitted. If you know what gets counted, what gets excluded, and where the common traps are, you can structure your finances to pass the assessment before you start looking at properties.

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Frequently Asked Questions