Short answer
This calculator converts a percentage property-value change into an indicative dollar amount, then shows how the same scenario changes equity and LVR if the secured loan balance stays unchanged.
Enter a fall as a negative percentage. For example, a 0.7% fall on a $1,000,000 starting value is a $7,000 decrease, producing a scenario value of $993,000.
The percentage is an assumption. A national or city index movement does not establish how one property changed in value.
Formula and methodology
The calculator uses three direct formulas:
Scenario value = starting property value x (1 + percentage change / 100)
Equity = property value - secured loan balance
LVR = secured loan balance / property value x 100
The loan balance does not change in the scenario. This isolates the mathematical effect of a different property value. Repayments, interest, redraw, offset balances, selling costs and lender policy are not modelled.
Worked example using a 0.7% fall
Assume a property value of $1,000,000 and a secured loan balance of $700,000.
- Entered value change: -0.7%.
- Dollar change: -$7,000.
- Scenario property value: $993,000.
- Starting equity: $300,000.
- Scenario equity: $293,000.
- Starting LVR: 70.00%.
- Scenario LVR: about 70.49%.
The example uses the July 2026 monthly movement in Cotality's national Home Value Index only as an arithmetic illustration. It is not a forecast for a particular property, suburb or future month.
What the result means
A lower entered property value reduces equity dollar-for-dollar when the loan balance is held constant. It also raises LVR because the same debt is divided by a smaller value.
That can be useful for planning a refinance, sale or equity scenario, but a lender may use its own valuation. Selling costs and the lender payout figure also matter if the property is being sold.
Use the Home Equity and LVR Calculator for a current-value scenario, the Property Selling Costs Calculator for an indicative sale position, or read how LVR is calculated in Australia.
Common mistakes
- Applying a national index movement directly to one home as if it were a valuation.
- Using the original purchase price when more recent evidence is available.
- Forgetting other loans secured against the property.
- Treating mathematical equity as approved or accessible borrowing.
- Ignoring selling costs when testing a sale scenario.
- Assuming an index will continue moving at the same monthly rate.
Sources and limitations
Cotality describes its Home Value Index as a hedonic index that controls for property characteristics and can be revised as later information arrives. The index measures market movement. It is not a valuation of the property entered here.
- Cotality: Australia's housing market downturn widens, published 3 August 2026 and checked 10 August 2026.
- Cotality: Home Value Index methodology, checked 10 August 2026.
General information disclaimer
This calculator provides general information and indicative arithmetic based on the assumptions entered. It is not a valuation, property forecast, financial advice, credit advice, loan offer, approval or recommendation. Property values and lender valuations may vary. Use current property-specific evidence and speak with a licensed professional where appropriate.
Last updated: 10 August 2026.
