Quick answer: Different lenders can produce materially different borrowing capacities because they assess income, expenses, existing limits and liabilities differently. The useful question is which inputs are driving the result and which can legitimately change.
Why two lenders can give different borrowing power for the same household
Borrowing power is not simply income multiplied by a fixed factor. A lender estimates assessable monthly income, deducts living expenses and commitments, then checks whether the proposed loan can be serviced using its assessment interest rate and loan term. Change any one input, and the maximum loan changes.
Two lenders might start with the same payslips and still disagree because one accepts more overtime, one applies a different spending benchmark, one assesses an existing loan differently, or one uses a different assessment-rate floor.
Try the Borrowing Power Calculator to change one variable at a time. It's a transparent scenario tool, not a representation of any individual lender's credit engine.
How the lender assessment is constructed
| Input | What may differ | What to check before applying |
|---|---|---|
| Base PAYG salary | Verified gross income and tax treatment | Current payslips, employment arrangements and consistency |
| Overtime, bonus and commission | History requirements and percentage accepted | Two years of actual receipts where available, role and recurrence |
| Self-employment | Financial period, addbacks, tax liabilities and business structure | Latest and comparative financials, retained profits, director wages |
| Rental income | Allowable percentage, rental costs and other property debt | Lease, statement, vacancy and costs |
| Household living costs | Declared expenditure versus benchmarks and lender categories | True recurring expenses, not an artificially low figure |
| Credit cards | Assessed commitment may be based on limit, not balance | Every open card and unused facility limit |
| HELP/HECS | Repayment commitments under current income arrangements | Current debt, repayment threshold and expected cessation |
| Other loans | Actual or assessed monthly debt commitments | Car loans, personal loans, BNPL and existing mortgages |
| Assessment rate | Buffer above the actual contract rate, possibly an additional floor | Compare stressed repayment, not just the quoted rate |
| Loan term | Different remaining periods change assessed monthly repayments | Real term, borrower age and any debt to be refinanced |
A lender may also treat interest-only repayments, dependants and the proposed property's ongoing costs differently. A single online prequalification number is therefore best used as a starting point.
Worked example: why an unused credit card matters
Take an illustrative household with monthly net income of $8,500, living expenses of $3,200, other debt commitments of $450, and a $15,000 credit-card limit. Assume an assessed card commitment of 3% of the limit each month ($450), a $300 monthly serviceability reserve, a 9% assessment rate and a 30-year principal-and-interest loan.
Under those assumptions, the borrowing model indicates roughly $510,000. Remove the unused card limit and the same assumptions produce roughly $566,000. That's an increase of about $56,000 without any increase in salary.
This is a sensitivity example, not a universal lender rule: the commitment rate, assessment buffer and other policy settings vary. Closing a card may require formal confirmation before a lender stops counting the limit. Try the card-limit field in the borrowing capacity calculator.
Worked example: a bonus is not necessarily worth its face value
Suppose one applicant earns an $110,000 base salary plus an average $30,000 annual bonus. Lender A recognises the full recurring bonus; Lender B assesses 60% ($18,000); Lender C excludes it pending a longer payment history.
That creates an assessable gross income range of $110,000–$140,000 before taxation and other lender adjustments. It does not translate directly to a $30,000 difference in loan size. The outcome depends on the tax treatment, remaining monthly commitments, stress rate and debt term. The better preparation is to substantiate the bonus history and compare documented lender treatment—not to claim a higher regular salary.
The same issue arises with shift allowances, casual work, seasonal income and commissions. The key question is how much of the income does the lender recognise, and for what reason?
Should you pay off HELP or keep the deposit?
Paying down HELP may reduce a current repayment obligation in a serviceability model, but it also takes cash away from the purchase. If $20,000 is needed to extinguish HELP completely, the capacity benefit needs to be compared against $20,000 less deposit, a potentially higher LVR and any additional LMI.
A partial repayment that does not change the assessed commitment may offer little immediate borrowing benefit. Ask which debt balance and repayment figure the lender will actually use, and whether a complete payout can be evidenced before approval. Model the resulting mortgage cash requirement in Deposit & Buying Costs.
Does a car loan reduce borrowing capacity?
Yes, where its repayments are included as a commitment. A $650 monthly car repayment is not simply subtracted from the amount you can borrow: it reduces the monthly capacity available to service the assessed mortgage repayment. The implied loan-size effect therefore depends on the assessment rate and mortgage term.
Before deciding to pay it out, compare the remaining car debt against the deposit and liquidity you would use. If the car loan is almost finished, ask how the lender treats that short remaining term rather than assuming it will disappear.
The seven questions to ask when lender estimates differ
- Which income line is different? Base pay, overtime, bonus, rent or self-employed addbacks?
- What monthly living expenses are being used? Actual verified amounts or a higher category benchmark?
- Which existing liabilities are counted? Check limits as well as balances.
- How is HELP treated? Current repayment or evidence of full payout?
- Which assessed interest rate and term are applied?
- What happens if the proposed mortgage is interest-only or an existing home is retained?
- What can be documented and changed before application? Focus on evidenced facts, not optimism.
Borrower questions answered
Does reducing a credit-card limit help even if I never use the card?
Potentially. If the lender calculates a monthly commitment using the available limit, lowering that limit can reduce the assumed commitment. Whether that improves the final lending limit depends on the complete assessment.
Can my borrowing power improve without changing jobs?
Yes. Removing an existing debt commitment, reducing unused revolving limits, documenting recurring variable income or changing the requested term can affect the model. The better outcome is not guaranteed, and paying off debt can reduce deposit cash.
Does a high credit score override insufficient servicing?
No. Credit conduct and affordability are different questions. Strong repayment history does not make a proposed mortgage affordable under an assessment model.
Why does a lender offer less than its website calculator showed?
The public calculator typically lacks the verified payslips, detailed expenses, liabilities, property information and lender-specific policy adjustments considered in assessment.
Can I apply using overtime or income from multiple jobs?
Some lenders recognise stable, evidenced income from multiple sources, possibly with different history or shading requirements. Prepare contracts, payslips, payment history and a realistic explanation of sustainability.
What if my circumstances change after pre-approval?
Income, employment, liabilities, assessed rates and property value can all affect final approval. Do not equate pre-approval with the final credit decision or an unconditional funding commitment.
Put borrowing power beside the actual purchase costs
A higher theoretical loan limit is not useful if the deposit plus duty, fees and moving costs are unavailable. Use the sequence:
Borrowing Power → Deposit & Buying Costs → Stamp Duty → Mortgage Repayments.
Explore the Home Loans Knowledge Centre for the full borrower decision process.
Get a lender comparison based on the actual inputs
If you've received inconsistent borrowing figures, the priority is identifying the policy differences that genuinely matter. GPS Finance combines intelligent lender matching with experienced credit judgement to structure and negotiate suitable options.
Check the purchase budget after improving the lending limit
A servicing increase and a usable purchase budget are different results. Removing a card limit can free capacity without using deposit cash; clearing HELP or a car loan can consume it. Compare the revised loan required with the revised lending limit after paying costs and keeping a reserve.
See pay off HECS or keep the house deposit for two worked purchase budgets. APRA also allows lenders to consider HELP expected to finish in the near term under their own policy; an immediate voluntary payout is not always the only route.
Sources and verification
- Moneysmart — Switching home loans
- Moneysmart — Mortgage offset accounts
- APRA — Macroprudential policy settings
These sources support the general mechanics and decision framework. Product availability, pricing, fees and lender policy can change. Tax-sensitive decisions should be checked against current ATO guidance and, where appropriate, a qualified tax adviser or accountant.
Related GPS Finance resources
- Equity Release and Cash-Out Refinancing: How Much Can You Access and Should You Take It Early?
- How Should a Prime Borrower Structure a Car Loan? Secured, Deposit, Balloon and Early Repayment
- Debt Consolidation for Strong-Credit Borrowers: When Does It Actually Save Money?
- Mortgage options
About the author: Krish Neelamraju is a finance and credit professional and founder of GPS Finance Group.
General information only. It is not personal financial, tax or legal advice. Finance approval, pricing, terms and structure are subject to lender assessment and the borrower’s circumstances.
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