Methodology · AU-HOME-022
How the Affordability Estimate works
This page documents how the Affordability Estimate produces its figures: the engines and formulas it runs, the rule packs it reads statutory values from, the official documents those packs cite, and how the engines are verified.
Engines and formulas
- E10 · Affordability estimate (lite)
Monthly surplus after an editable expense floor, converted to an indicative range via the §13.5 payment formula at your rate plus an editable buffer. A range, never an approval.
Registered formulas: §13.5 payment
Verification
Engines carry boundary tests at every bracket edge, property-based tests, reconciliation invariants and, where official worked examples exist, tests that reproduce them exactly. The full source register is on the sources page.