Understanding Serviceability
What is serviceability, and how do lenders decide whether I can afford a loan?
By Andrew, franklenn FINANCE 7 min readUpdated 3 November 2026
The short answer
Serviceability is a lender's test of whether you can afford the repayments on a loan, both now and if rates rise. The lender takes your income, subtracts your living expenses and the repayments on all your debts, then checks there's money left over, using an assessment rate that is higher than the actual rate. Credit card limits, HECS-HELP debt, dependants and how your income is earned all affect the result. It's often the real limit on borrowing, more than deposit or equity.
Detailed explanation
What serviceability actually measures
In simple terms, the lender builds a monthly budget for you. Income goes in one column, and living expenses, existing debt repayments and the proposed new loan repayment go in the other. If there's a surplus, the loan services. If there's a shortfall, it doesn't, regardless of how much equity or deposit you have.
Each lender uses its own calculator, so the same application can pass with one lender and fail with another. That variation is a big part of why a broker can help.
Lenders also look at the stability of your situation, not just the numbers. How long you've been in your job, whether you're on probation, and your recent account conduct, such as missed payments or regular overdrawn balances, can all influence whether an application is approved.
The assessment rate buffer
Lenders don't test your loan at the rate you'll actually pay. Under guidance from the banking regulator, APRA, they add a buffer, currently at least 3 percentage points, on top of the actual rate. So if your rate is 6.09%, the lender may check whether you could still afford repayments at 9.09%. The buffer is set by APRA and can change, so check current settings or ask us.
Lenders also test existing home loans you hold elsewhere at their own assessment rate, not your actual repayment, which can reduce how much you can borrow.
Expenses and debts: the details matter
Lenders compare your declared living expenses with a benchmark based on your household size and income, and use whichever is higher. They will also look at your bank statements, so your declared figures need to be realistic.
It helps to review three months of bank statements before you apply, as a lender would. Recurring subscriptions, regular takeaway spending and gambling transactions are all visible, and while normal spending is fine, a clear and consistent picture makes the assessment smoother.
- Credit cards are counted on the limit, not the balance. Many lenders assume a monthly repayment of around 3% to 3.8% of the limit.
- HECS-HELP repayments reduce your take-home income.
- Car loans, personal loans and buy now pay later accounts count as commitments.
- Dependants increase the expense benchmark.
How income is counted
Base salary is usually counted in full. Overtime, bonuses, commissions and allowances may be shaded or need a track record. Rental income is typically counted at a reduced percentage. Self-employed income is usually based on the last one or two years of tax returns, and some lenders will consider add-backs such as depreciation. Our guide on how lenders assess income goes into more detail.
Ways to improve serviceability
Some improvements are quick, and others take planning. The aim is not to squeeze every last dollar out of a lender but to borrow an amount that works comfortably for your household.
It's also worth remembering that the maximum a lender will approve is not a target. Leaving some headroom in your budget gives you room to absorb rate rises, a drop in income or the arrival of a new family member without stress.
- Reduce or cancel unused credit card limits.
- Pay off small personal or car loans where it makes sense.
- Review your spending in the months before applying.
- Choose a lender whose policy suits how you earn your income.
- Consider loan term and repayment type, understanding the trade-offs.
Worked example
How the buffer and a credit card change the numbers
An illustrative example. A household applies for a $600,000 loan over 30 years at an actual rate of 6.09% p.a. The lender assesses at 9.09% p.a. They also hold a credit card with a $12,000 limit, which this lender counts at 3.8% of the limit each month.
| Loan amount | $600,000 |
| Monthly P&I repayment at 6.09% | $3,632.09 |
| Monthly repayment tested at 9.09% | $4,866.64 |
| Difference the household must show it can absorb | $1,234.55 a month |
| Credit card limit | $12,000 |
| Assumed monthly card commitment (3.8%) | $456 |
| Total monthly commitment the lender tests | $5,322.64 |
Even if the card is paid off every month, it adds $456 a month to the lender's calculation. Reducing the limit or closing an unused card could noticeably improve borrowing capacity. Numbers are illustrative; each lender's method differs.
Illustrative only. Figures are examples, not a quote or a recommendation.
Common mistakes
- Underestimating living expenses, which lenders will check against bank statements.
- Keeping large credit card limits you don't use.
- Assuming the lender uses your actual rate for its calculation.
- Applying with several lenders at once, which can leave multiple enquiries on your credit file.
- Ignoring how existing loans elsewhere are assessed.
- Borrowing the maximum without checking it suits your real budget.
Frequently asked questions
Next steps
Talk to franklenn FINANCE
If you'd like to know how lenders are likely to see your finances, book a free discovery call with franklenn FINANCE and we'll run your numbers across a range of lenders.
This guide is general information only and does not consider your objectives, financial situation or needs. It is not financial, tax or legal advice. Lender policies, rates and government schemes change. Please speak with us, and with your accountant or solicitor where relevant, before acting.