How to Calculate and Improve Your Borrowing Capacity for a Home Loan in Australia

Buying a home is one of the most significant financial commitments you can make, and understanding your borrowing capacity is the crucial first step. Your borrowing capacity—or borrowing power—determines how much a lender is willing to lend you based on your financial situation. In Australia, this calculation has become more complex in recent years due to regulatory changes, rising interest rates, and cost-of-living pressures. This guide explains the key factors lenders assess, how to calculate your own borrowing capacity, and actionable strategies to improve it.


What Is Borrowing Capacity?

Borrowing capacity is the maximum amount a lender will lend you for a home loan, based on an assessment of your income, expenses, debts, and overall financial stability. Lenders use this figure to ensure you can comfortably repay the loan without undue financial stress. It’s not just about how much you earn—your spending habits, existing liabilities, and even the number of dependents can significantly influence the outcome.

In Australia, lenders are required by law to lend responsibly. The Australian Prudential Regulation Authority (APRA) and the Australian Securities and Investments Commission (ASIC) enforce strict serviceability standards. As of 2025, most lenders apply an interest rate buffer of 3% above the loan’s actual rate when assessing your ability to repay. This means you’re tested on whether you could afford the loan if rates were significantly higher than today’s levels.

Why It Matters

Knowing your borrowing capacity helps you:

• Set a realistic property budget.
• Avoid disappointment when applying for a loan.
• Identify areas to improve before applying.
• Compare loan products more effectively.

Key Factors Lenders Consider

Lenders assess your borrowing capacity using a comprehensive set of criteria. Here are the primary factors:

1. Income

Your income is the starting point. Lenders consider:

• Gross annual salary (for PAYG employees).
• Net profit (for self-employed borrowers, typically averaged over two years).
• Rental income (from investment properties, usually at 75-80% of expected rent).
• Other income (e.g., bonuses, commissions, overtime, dividends, government benefits).

Lenders may shade or discount certain types of income. For example, only 80% of bonuses and overtime may be accepted unless you can show consistent history. Self-employed borrowers often face stricter scrutiny, requiring two years of tax returns and financial statements.

2. Expenses

Living expenses are a critical part of the assessment. Lenders use one of the following:

• Household Expenditure Measure (HEM) : A benchmark based on median spending for your household size and location.
• Self-declared expenses : You provide a detailed breakdown of your spending.

Lenders will generally use the higher of the two. Common expense categories include:

• Housing (rent or current mortgage).
• Utilities.
• Groceries.
• Transport.
• Education and childcare.
• Insurance.
• Entertainment and lifestyle.

3. Existing Debts

All existing liabilities reduce your borrowing capacity. These include:

• Credit card limits (not just balances—lenders assume the limit could be fully drawn).
• Personal loans.
• Car loans.
• HECS-HELP debt.
• Other mortgages.

Even if you pay off your credit card each month, the lender will factor in the total credit limit as a potential liability.

4. Credit History

Your credit score and report from agencies like Equifax, Experian, or illion play a vital role. Lenders look for:

• History of on-time repayments.
• Number of credit inquiries.
• Defaults or bankruptcies.
• Credit utilisation ratio.

A strong credit history can lead to better interest rates, while a poor history may reduce your borrowing capacity or lead to outright rejection.

5. Loan Type and Term

The structure of the loan also matters:

• Loan term : Shorter terms mean higher monthly repayments but less total interest. A 30-year term is standard and maximises borrowing capacity.
• Repayment type : Principal-and-interest loans are assessed more favourably than interest-only loans.
• Interest rate : A lower rate increases capacity, but lenders apply the buffer rate for assessment.

6. Dependents

The number of dependents (children or non-working adults) impacts your expense assumptions. Lenders have minimum living expense benchmarks that increase with household size.

7. Loan-to-Value Ratio (LVR)

A lower LVR (i.e., a larger deposit) reduces risk for the lender and may improve your borrowing capacity. Borrowers with an LVR above 80% typically require Lenders Mortgage Insurance (LMI), which adds to the cost but doesn’t directly reduce the loan amount.

How to Calculate Your Own Borrowing Capacity

While only a lender can give you a precise figure, you can estimate your borrowing capacity using these steps:

1. Calculate your net monthly income after tax.
2. Subtract all monthly expenses (use the higher of HEM or your actual spending).
3. Subtract existing loan repayments and other commitments.
4. Apply a serviceability buffer (add 3% to current interest rates).
5. Use an online calculator from a reputable source to estimate the maximum loan amount.

Example Calculation

Consider a couple earning a combined $150,000 p.a. with no children, a $10,000 credit card limit, and a $500/month car loan. Using a 6.00% assessment rate (3% buffer on a 3.00% loan), their estimated borrowing capacity might be around $650,000. However, this varies widely by lender.

*Assumes 30-year loan term, 3% buffer, and standard lender criteria. Figures are indicative only.

Practical Steps to Improve Your Borrowing Capacity

If your borrowing power is lower than expected, take these steps to strengthen your application:

1. Reduce or Eliminate Debts

Pay down credit cards and personal loans. Even small reductions can have a big impact because lenders assess based on limits, not balances. Consider consolidating debts with a lower-rate personal loan, but be cautious of extending the term.

2. Lower Your Credit Card Limits

If you have a $15,000 credit card limit but rarely use it, reduce it to a more reasonable level. Lenders will treat the lower limit as your potential liability.

3. Trim Living Expenses

Review your spending for at least three months before applying. Cut non-essentials like streaming services, dining out, and unused subscriptions. Lenders will scrutinise bank statements, so genuine savings habits matter.

4. Improve Your Credit Score

• Pay all bills on time.
• Avoid multiple credit applications in a short period.
• Keep credit utilisation below 30%.
• Check your credit report for errors and dispute any inaccuracies.

5. Increase Your Deposit

A larger deposit (lower LVR) reduces the lender’s risk and may increase your borrowing capacity. It also helps you avoid LMI, saving thousands.

6. Consider a Longer Loan Term

Opting for a 30-year term instead of 25 years lowers monthly repayments, which can boost your assessed capacity. However, you’ll pay more interest over the life of the loan.

7. Include All Eligible Income

Ensure you declare all income sources: bonuses, overtime, rental income, family tax benefits. Provide documentation to support consistency.

8. Choose the Right Lender

Different lenders have different policies. Some are more generous with certain income types or have lower expense benchmarks. A mortgage broker can help match you with a suitable lender.

Common Mistakes That Reduce Borrowing Capacity

• Not checking your credit report before applying.
• Changing jobs shortly before or during the application process (lenders prefer stable employment).
• Taking on new debt (e.g., buying a car on finance) before settlement.
• Underestimating living expenses in your self-declaration, which can look unrealistic.
• Applying with multiple lenders simultaneously, which hurts your credit score.

How Lenders Assess Serviceability in 2025

In 2025, the lending landscape continues to evolve. APRA’s serviceability buffer remains at 3%, but some lenders may apply a higher floor rate for certain borrowers. The rise of comprehensive credit reporting (CCR) means lenders see more granular data on your repayment history. Additionally, the Reserve Bank of Australia’s (RBA) cash rate decisions directly impact assessment rates.

According to the Australian Bureau of Statistics (ABS), average weekly earnings rose by 3.5% in 2024, but living costs increased by 4.2% over the same period. This wage-cost gap has tightened borrowing capacity for many households. Lenders are also paying closer attention to buy-now-pay-later (BNPL) services like Afterpay, treating them as ongoing commitments.

FAQ

How much can I borrow on my income?

It depends on your expenses, debts, and the lender’s criteria. As a rough guide, lenders may lend 5-6 times your gross annual income, but this varies. Use an online borrowing capacity calculator for a personalised estimate.

Does a bigger deposit increase my borrowing capacity?

Yes, a larger deposit reduces the loan-to-value ratio (LVR), which lowers risk for the lender. It can also help you avoid Lenders Mortgage Insurance (LMI), freeing up capacity for the loan itself.

Can I get a home loan if I’m self-employed?

Yes, but you’ll need to provide two years of tax returns and financial statements. Lenders may average your net profit and apply stricter verification. Some specialist lenders cater to self-employed borrowers with alternative documentation.

How do credit cards affect my borrowing capacity?

Lenders treat your credit card limit as a liability, even if you pay it off monthly. Reducing your limits can significantly improve your borrowing power.

Should I fix my interest rate to improve borrowing capacity?

Fixing your rate doesn’t directly increase your capacity because lenders assess you at a higher buffer rate. However, a lower fixed rate could reduce your actual repayments, making the loan more affordable in practice.

References

1. Australian Prudential Regulation Authority (APRA), Prudential Practice Guide APG 223 – Residential Mortgage Lending, 2024 update. https://www.apra.gov.au
2. Australian Securities and Investments Commission (ASIC), Responsible Lending Guidelines, 2023. https://asic.gov.au
3. Reserve Bank of Australia, Statement on Monetary Policy, May 2025. https://www.rba.gov.au
4. Australian Bureau of Statistics, Average Weekly Earnings, Australia, November 2024. https://www.abs.gov.au
5. Equifax, Understanding Your Credit Score, 2025. https://www.equifax.com.au