Investment Property Loan Calculator (Australia)

Use this investment property loan calculator to estimate repayments, loan-to-value ratio (LVR), first-year interest, and the difference between principal-and-interest and interest-only repayment structures. Enter the purchase price, deposit, interest rate, and loan term above to model a simple investor loan scenario.

This calculator is a repayment estimate only. It does not test lender serviceability, quote a live interest rate, include lender fees, or decide whether a loan structure is suitable for you.

What does the investment property loan calculator show?

The calculator focuses on the borrowing inputs that feed into property-investment modelling:

• Loan amount — purchase price minus deposit
• LVR — loan amount divided by property price
• Monthly repayment — based on the repayment type you select
• Weekly repayment equivalent — monthly repayment annualised and divided by 52
• First-year interest estimate — useful when modelling loan-interest costs
• Principal repaid in year 1 — shown for principal-and-interest loans
• Deposit needed for 80% LVR — a quick check before using the LMI calculator

It is deliberately narrower than the full investment property calculator. Use this page when you want to isolate the loan mechanics before layering on rent, expenses, land tax, depreciation, and CGT.

Principal-and-interest vs interest-only repayments

Investment property loans are commonly modelled under two repayment structures.

Principal and interest means each repayment includes interest plus a principal component. The repayment is higher, but the loan balance gradually falls over the term.

Interest-only means the repayment covers interest only for the period being modelled. The repayment is lower, but the loan balance does not reduce during that interest-only period.

The calculator shows both monthly repayment estimates side by side, then highlights the extra monthly cash flow required for principal-and-interest repayments.

Worked example: $750,000 property with 20% deposit

Assume an investor is considering a $750,000 property with a $150,000 deposit, a $600,000 loan, a 6.5% annual interest rate, and a 30-year term.

The interest-only repayment is lower, but the full loan balance remains outstanding. The principal-and-interest repayment is higher because part of each repayment reduces the loan.

How LVR affects the next calculation

LVR is one of the fastest ways to sanity-check a loan scenario. At 80% LVR, the deposit is 20% of the purchase price. Above 80% LVR, lenders mortgage insurance may apply depending on the lender, borrower, property type, and loan structure.

If your scenario is above 80% LVR, use the LMI calculator after this page to estimate the possible extra upfront or capitalised cost.

How this connects to negative gearing

The first-year interest estimate from this calculator can be used as the loan-interest input in the negative gearing calculator or investment property tax deductions calculator.

Only interest is generally relevant to rental deduction modelling. Principal repayments are cash flow, but they are not loan-interest deductions. If your loan is split, refinanced, redrawn, or partly used for private purposes, confirm the deductible portion with a registered tax agent.

What is not included?

This calculator does not include:

• Stamp duty or transfer duty
• Conveyancing, inspections, or buyer agent fees
• LMI premiums
• Offset-account balances
• Extra repayments or redraws
• Rate changes during the loan term
• Fixed-rate expiry or refinancing
• Lender serviceability rules
• Tax outcomes beyond the first-year interest estimate

For a whole-property view, use the investment property calculator or the property investment spreadsheet.

Formula used

For principal-and-interest repayments, the calculator uses the standard amortisation formula:

Monthly repayment = P x r x (1 + r)^n / ((1 + r)^n - 1)

Where P is the loan amount, r is the monthly interest rate, and n is the number of monthly repayments.

For interest-only repayments:

Monthly repayment = loan amount x annual interest rate / 12

The figures are rounded for display. Actual lender repayments may differ because of fees, repayment frequency, rate type, offset balances, and lender-specific calculation methods.