Effective from 13 February 2025.
Open official source ↗Calculation methodology
See where the numbers come from.
The Broker Room separates official government-rule calculations from user-directed planning maths. This page shows the source register, verification dates and the boundaries used to stop unsupported assumptions from becoming estimates.
Verification process
How a rule becomes a calculator result.
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01
Start with an official source
Government revenue, legislation, gazette and land-registry sources are preferred over secondary summaries.
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02
Record the rule period
Effective and expiry dates are kept with the rule where they are available, so a future fee period is not silently treated as current.
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03
Test boundaries and exceptions
Thresholds, ownership shares, grants, concessions and unsupported situations are covered by automated tests before a release is accepted.
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04
Fail closed when a safe answer is not available
The calculator asks for more detail, excludes an unverified amount or stops the estimate rather than inventing a replacement rule.
South Australia
Official-source register.
Rules verified 23 August 2026
Effective from 13 February 2025.
Open official source ↗Effective 1 July 2026 to 30 June 2027.
Open official source ↗Effective 1 July 2026 to 30 June 2027.
Open official source ↗Effective from 13 February 2025.
Open official source ↗Effective from 13 February 2025.
Open official source ↗Effective from 1 January 2018.
Open official source ↗Effective from 25 March 2026.
Open official source ↗Effective from 4 June 2026.
Open official source ↗Planning maths
What the non-government tools actually calculate.
Property purchase planner
Adds the property price and only the government, construction and private costs you enter, then compares that total with the available funds you enter. It does not infer a loan amount, LVR or borrowing capacity.
Open purchase planner →Home loan repayment calculator
Uses standard principal-and-interest amortisation maths with the loan amount, annual rate, term and repayment frequency you choose. It is not a lender quote or serviceability assessment.
Open repayment calculator →Home Loan Scenario Planner
Compares a baseline with the rate, offset, extra repayment and lump-sum changes you enter. Rates remain constant within each projection and lender-specific policy is not modelled.
Open scenario planner →Indicative borrowing estimate
Monthly available repayment is the entered after-tax household income less entered living expenses and debt repayments, floored at zero. The selected interest rate is increased by 3 percentage points, then standard inverse principal-and-interest amortisation converts the monthly repayment into an indicative principal. The result is rounded down to the nearest $1,000. This generic model does not apply lender expense benchmarks, income shading, credit-limit treatment, dependants, assessment floors or product policy.
Buffer reference verified 3 September 2026.
Open APRA reference ↗The boundary matters
Transparent arithmetic is not personalised credit advice.
The calculators do not recommend a lender or product or tell a visitor how much they should borrow. The optional borrowing-position tool is a generic repayment-based estimate and is not lender serviceability, borrowing capacity, a credit assessment or loan approval. Personalised credit assistance is separate and handled by an authorised mortgage broker.