Show the working.
A calculator is only as trustworthy as the numbers underneath it. Here is exactly where ours come from and how they are computed.
Every figure traces to a primary source.
The assumptions behind the tools are taken from official Australian sources, not third-hand summaries:
- RBA — the cash rate and the rate environment that flows from it.
- ATO — income tax brackets, thresholds, offsets and superannuation rules.
- APRA — the serviceability buffer lenders are required to apply.
- ABS — wage, price and property data.
- State revenue offices — stamp duty schedules and first-home concessions, which differ in every state and territory.
Deterministic math, not guesswork.
Each calculator uses the same standard formula a bank or the ATO uses internally — amortisation, compound growth, marginal tax, loan-to-value ratio, and so on. The math is deterministic: the same inputs always produce the same result, and every step can be checked.
The AI explains. It does not compute.
An optional AI co-pilot turns the result into plain English for your situation. It does not do the arithmetic — the numbers come from the formulas above. The AI is a language model and it can be wrong, so treat its commentary as a starting point to verify, not a verdict to act on.
Refreshed when the official numbers change.
Rates, brackets and medians move. Market assumptions are updated from official releases, and each tool shows the date it was last reviewed so you are never guessing how current it is.
These are estimates — verify before you act.
The tools use simplified models. They cannot capture every detail of your circumstances, and lender or government policy can change without notice. Always confirm the specifics with the lender, the ATO, or a licensed adviser before making a decision.
Found a number that looks wrong?
Accuracy is the whole point. If a figure looks off, say which tool and what you expected — corrections are made quickly.
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