Usable Equity vs Theoretical Equity

Usable Equity vs Theoretical Equity

The distinction

Theoretical equity is the simple arithmetic difference between what a property is worth and what is owed against it. If a property is valued at $1,000,000 and the existing mortgage is $400,000, the theoretical equity is $600,000.

Usable equity is the amount that can actually be accessed as new borrowing, after applying the lender's 80% LVR ceiling.

The formula: (Property value × 80%) − existing debt = usable equity

Using the example above:

• $1,000,000 × 80% = $800,000
• $800,000 − $400,000 = $400,000 usable equity

The remaining $200,000 in theoretical equity (between $800,000 and $1,000,000) cannot be accessed without LMI.

The valuation constraint

The lender orders an independent valuation. The number used for the usable equity calculation is the lender's assessed value — not the owner's estimate, not a recent sales comparison, not the local agent's appraisal. If the lender's valuation comes in below the owner's expectation, the usable equity figure is lower.

In a market where values are flat or falling, valuations may be more conservative. An owner who is expecting to access $400,000 may find the lender's valuation produces only $300,000 of usable equity.

The serviceability constraint

Even where usable equity exists, the borrower must also demonstrate that their income can service the new total debt at the APRA stress buffer rate. Usable equity is a ceiling on the amount available to borrow — it is not a guarantee that the borrower can access the full amount.

If a borrower has $400,000 in usable equity but their income can only support an additional $200,000 in borrowing, the equity release is limited to $200,000.

LMI may be required if the top-up takes LVR above 80%

If an equity release takes the combined borrowing above 80% of the property value, LMI is required. In practice, most borrowers structure equity releases to stay at or below 80% LVR to avoid this cost. If going above 80% is necessary, the LMI cost needs to be factored into the decision.