Collections

A single calculator answers a single question. Working out whether you can afford a house, or what a job offer is really worth, means answering several in the right order — because the output of one is the input to the next, and starting in the wrong place is how people end up with a repayment figure that ignores lender’s mortgage insurance.

Each collection below sets out the sequence, explains what each step tells you, and is honest about the costs the tools leave out. They are groupings of the existing calculators, not extra copies of them — every tool still has its own page, formula, worked example and sources. For the reasoning behind a particular calculation, the guides go deeper.

How a collection differs from a category

A category is a filing system: it groups tools by subject, so everything about money sits in one place and everything about dates in another. That is useful when you already know what you are looking for.

A collection is a route through a task. It crosses categories when the task does — working out what a job offer is worth touches pay, tax and superannuation — and it puts the tools in a deliberate order, because the answer from one step is the input to the next. Each collection also spells out the costs and complications the tools leave out, which is usually where a plan goes wrong.