Estimate Your Borrowing Power
Use this calculator to estimate how much you may be able to borrow for a home loan based on income, expenses, debt, and interest rates.
What this “How Much Can I Borrow” calculator tells you
A borrowing power calculator gives you a practical estimate of your potential loan size before you apply with a bank or mortgage broker. It uses your income, monthly obligations, and a repayment model to estimate an amount you may be able to service comfortably.
This tool is helpful if you are planning to buy your first home, upgrade to a larger property, or compare scenarios such as changing your deposit, reducing debt, or extending your loan term.
How lenders usually assess borrowing capacity
Different lenders use different formulas, but most serviceability checks include the same core factors:
- Income: Salary, self-employment income, rental income, and other acceptable earnings.
- Existing debts: Credit card minimums, personal loans, auto finance, and student debt commitments.
- Living expenses: Everyday costs such as groceries, transport, utilities, healthcare, and childcare.
- Interest rate buffers: Lenders often test repayments at a higher “assessment rate” than your actual rate.
- Loan term: A longer term can reduce monthly repayments, increasing apparent serviceability.
- Policy caps: Some institutions apply income multiple caps or debt-to-income limits.
How this calculator works
1) Serviceability estimate
The calculator first estimates a usable monthly surplus from your gross monthly income after debts and living expenses. It then converts that surplus into a potential loan amount using an amortization formula.
2) Income multiple cap
The model also applies an income multiple cap (for example, 5.5x total annual income). Your final borrowing estimate is the lower of:
- Serviceability-based loan amount, and
- Income multiple cap amount.
3) Purchase budget estimate
Finally, the calculator adds your deposit to estimate a rough purchase budget. Remember that stamp duty, legal fees, inspections, and lender fees can reduce how much of your deposit is available for the property itself.
Ways to increase how much you can borrow
- Pay down short-term debts with high monthly repayments.
- Reduce discretionary spending for at least 3–6 months before applying.
- Avoid taking on new liabilities (car loans, credit cards) during pre-approval.
- Improve your credit profile by paying all obligations on time.
- Increase deposit size to reduce risk and improve loan structure options.
- Consider a longer loan term (while understanding total interest trade-offs).
Common mistakes to avoid
Ignoring total ownership costs
Mortgage repayments are only one part of the budget. Include council rates, insurance, maintenance, strata/body corporate fees, and utilities.
Assuming online calculators are guaranteed approvals
Calculator outputs are estimates. Final approval depends on full document review, lender policy, valuation outcomes, and your credit profile at submission.
Borrowing right at your maximum
Qualifying for a loan does not always mean it is comfortable for your lifestyle. Building in a monthly buffer can protect you from future rate rises or income disruptions.
Quick example
Suppose a household earns $100,000 total annual income, has $2,650 in combined monthly debts and living costs, and plans a 30-year loan. At a 6.25% rate (plus serviceability buffer), the estimated borrowing power may land significantly below what an income-only rule suggests. This is why controlling monthly commitments can be just as important as increasing income.
Final thought
Use this calculator as a planning tool to understand your range, test scenarios, and identify the strongest next move. For a real borrowing figure, speak with a qualified mortgage broker or lender and request a full serviceability assessment.